* un-: This is the most common prefix for negation, used with many words.
* Examples: unhappy, unable, unbreakable
* in-: Used before words starting with "l" or "m" and often before words of Latin origin.
* Examples: incomplete, incapable, incorrect
* im-: Similar to "in-", but used before words starting with "p", "b", or "m".
* Examples: impossible, improbable, immoral
* ir-: Used before words starting with "r".
* Examples: irregular, irrelevant, irresponsible
* non-: Used for words that are not directly related to a specific action or quality.
* Examples: non-fiction, non-profit, non-smoker
* a-: Used before words of Greek origin and sometimes for words beginning with "l" or "n".
* Examples: atypical, amoral, asexual
The best prefix to use depends on the specific word and its origin.