What's the difference between dis- and mis- or between un- and non-? This negative prefix list can help you understand the prefixes that can change a word's meaning into its opposite.
Note: I have added the parts of speech (verb, adjective, noun) to the prefix list examples because some people have been looking for negative adjectives or negative verbs.
Go straight to the examples:
Note that sometimes one prefix is used for an adjective, and different ones are used for related nouns or verbs.
Usually, however, the same prefix serves both adjective and noun: uncertain, uncertainty; unwilling, unwillingness; unfriendly, unfriendliness, inadequate, inadequacy, disloyal, disloyalty, etc.
Examples: deactivate, decode, decommission, decompose, deconstruct, decontaminate, decrease, deflate, deflect, deform, demythologize, derail, detract.
The list above is all verbs. Any of them could be made into adjectives by adding -ed (or -d if the verb ends in 'e' already: decoded, deflated, etc.) Several could also be made into nouns: deactivation, decomposition, decontamination, deflation, etc. Decrease can be used as a noun as it is.
Note that the prefix de- in Latin (and in words that originate in Latin) has other, contrary meanings as well as sometimes making words negative. (See List of Prefixes.) It is often used as an intensifier, meaning completely (as in demand), as well as meaning from, down, or away. When used with an English verb to make a new word, it works as a negative. (Debug, defrost, devalue.)
Examples (verb/ adjective/ noun or vb/ adj when all or both are common): disaffected (adj.), disagree/ disagreeable/ disagreement, disbelief (noun), dishonor (vb. or noun)/ dishonored or dishonorable, disinfect/ disinfected/ disinfection, disinherit/ disinherited, disloyal (adj.) & disloyalty (noun), displease/ displeased or displeasing/ displeasure, disproportionate (adj.), distasteful (adj.) and distaste (noun), distrust (vb. or noun)/ distrustful (adj.).
(Tasteful refers to something that shows good taste or judgment. Things which are pleasant to the taste buds are ‘tasty.’ Distasteful refers to tasks that are unpleasant. Foods that lack flavor are tasteless. A lack of good taste in aesthetics can also be called tasteless.)
In- often changes to 'il-' before l; 'im-' before b, m, or p; and 'ir-' before r. These changes make it easier to pronounce.
Adjective Examples: illegal, illegible, illiterate, illogical, immature, impatient, imperfect, impossible, imprecise, inaccessible, inaccurate, inadequate, inappropriate, incapable, incoherent, incompatible, incomplete, inconceivable, inconsistent, incredible, indefinite, indiscreet, inevitable, infinite, inflexible, insecure, insignificant, insubordinate, insufficient, invalid, invariable, invisible, involuntary, irrational, irregular, irrelevant, irreparable, irresistible, irresponsible, irreversible, etc.
A few noun examples using the same roots: illegibility, illiteracy, immaturity, impatience, imperfection, impossibility, imprecision, inaccessibility, inaccuracy, inadequacy, inappropriateness, incapability, incoherence, incompatibility, incompleteness, inconsistency, indiscretion, inevitability, infinity, inflexibility, insecurity, insignificance, insubordination, insufficiency, invalidity, invariability, invisibility, irrationality, irregularity, irrelevance, irresponsibility.
Most of these do not have verb forms.
Exceptions in which ‘in-‘ does not negate, but intensifies: Inflammable has the same meaning as flammable-- something that burns easily. Their opposite is nonflammable. The same is true for habitable and inhabitable (the negative is uninhabitable).
Valuable and invaluable also are synonyms— except that invaluable is even stronger. It means something is priceless: so valuable that a person would not want to give it up for any amount of money.
Examples: misconduct (noun), misdemeanor(noun), misdiagnose (to diagnose wrongly)/ misdiagnosed/ misdiagnosis, misinform/ misinformed/ misinformation, misinterpret/ misinterpreted/ misinterpretation, mislead/ misled or misleading, misplace/ misplaced, misspell/ misspelled/ misspelling, mistake/ mistaken/ mistake, mistrust (both a noun and a verb, but weaker than distrust), misunderstand/ misunderstood/ misunderstanding.
A misdiagnosed disease has been diagnosed incorrectly, as compared to an undiagnosed disease, which has not been diagnosed at all.
Similarly, a misinformed person has been given wrong information, while an uninformed person simply does not know much about a subject.
Voice of America's Learning English has an excellent article on the difference between 'misinformation' and 'disinformation.'
(They both refer to information that is not true, but disinformation is intentionally deceptive. People who share misinformation may not realize it's false.)
You can also listen to an audio version of the article and find definitions of all its key words.
Examples-- nouns: nonconformist or nonconformity, nonentity, nonexistence, nonintervention, nonsense, etc.
Adjectives: nonconforming, nonexistent, nonmetallic, nonpartisan, nonresident, nonrestrictive (but unrestricted), nonsensical, nonstop.
I can't think of any verbs that begin with non-.
Some words can be negated either with non- or with another negative. In those cases non- has a more neutral connotation. For example, nonstandard means not according to the usual standard, but substandard is below the standard: not good. Nonreligious means not religious, but irreligious means more actively opposed to religion.
(Adjective) Examples: unable, unacknowledged, unaffected (not affected at all; disaffected means affected badly), unafraid, unaided, unaltered, unambiguous, unanticipated, unapproachable, unassigned, unattainable, unavailable, unaware, unceasing, uncertain, unclear, unconventional, uncooperative, uncoordinated, unenforced, unexposed, unfocused, unfriendly*, unhelpful, uninformed, unknown, unmodified, unnatural, unpleasant, unpredictable, unprofessional, unrealistic, unrefined, unresolved, unscheduled, unstable, untouched, unwilling, etc.
*(in this case -ly isn’t for an adverb. Both friendly & unfriendly are adjectives.)
A few of these have related nouns including unavailability, uncertainty, unenforceability, unpleasantness, unpredictability, unreality, and untouchability, as well as inability, instability, and irresolution.
Some also have related adverbs: unambiguously, unceasingly, uncertainly, unconventionally, unnaturally, unpleasantly, unpredictably, unprofessionally, unrealistically, unwillingly, and possibly others.
Very few are verbs: undo and (only informally, on Facebook) unfriend.
There are many more examples of negative prefixes on 50 Word Roots, though not nearly all the possible forms. (You can make almost any adjective negative with ‘un-’ except the negatives that we carried over from Latin with ‘in-‘ (or ‘il-‘, ‘im-‘ or ’ir-‘. Remember that these 'in-' prefixes can also mean ‘in’ or ‘into.’)
You can find the negative prefixes on that page both in the main list and sometimes pointed out, especially when different forms of a word take different negative prefixes.
I counted the different negative prefix uses—all useful words that I have read and might use. None of these Latin roots took the prefix ‘mis-.‘ Four (nouns and adjectives) took ‘non-,‘ 13 took ‘de-‘; 9 ‘dis-‘ 22 ‘in-‘’im-‘, etc., and well over 30 (not all written down) took ‘un-.’
Other prefixes, besides the 6 on this negative prefix list, can also give a negative connotation to words. (Note 'sub-' above.) A- an-, anti-, contra- counter-, and ob- also often negate the meaning of a root.
(For examples, see List of Prefixes for each of these, or the Facebook Comments below for a-: amoral-- not moral, etc.) The six at the top of this page are used the most in common English, however. They are worth knowing!
The best way to learn the different negative prefixes is to work (or play) with them. You can do both on Practice Negative Prefixes. It emphasizes academic vocabulary, so is also a good way to review about 60 common words on the Academic Word List.
If you teach English, be sure to check out Root, Prefix, and Suffix Worksheets.
The Common Prefix packet contains printable pdf lessons with all the information from this page, the List of Prefixes, and a great deal of practice (with negative prefixes as well as all the most common prefixes). There are also root, suffix, and combination packets.