General Negation:
* un-: undo, unhappy, unclear
* in-: inactive, ineligible, incorrect
* non-: non-profit, non-fiction, non-essential
* dis-: disagree, dishonest, disapprove
* im-: impossible, imperfect, impatient
* ir-: irresponsible, irregular, irrelevant
* il-: illegal, illiterate, illogical
* a-: asymmetrical, atypical, amoral
Note:
* The choice of prefix depends on the specific word and its origin.
* Some prefixes are more common than others. For example, "un-" is very common, while "a-" is less common.
* Some words can have more than one possible negation prefix, leading to synonyms like "unhappy" and "discontent."
There are also a few less common prefixes that indicate negation, like "de-" (deactivated) and "mis-" (misunderstood), but these are less frequently used.