* Un- means "not" or "the opposite of." It is used to create the opposite of a word.
* Examples: happy/unhappy, tied/untied, real/unreal
* Re- means "again" or "back." It indicates a repetition or return to an earlier state.
* Examples: replay, rewind, rebuild
* Im- is a prefix that usually means "not" or "lack of." It's often used before words beginning with "m" or "p."
* Examples: impossible, immoral, impatient
* Ir- is also a prefix meaning "not" or "lack of." It's often used before words beginning with "r."
* Examples: irregular, irrelevant, irresponsible
* Il- is another prefix meaning "not" or "lack of." It's usually used before words beginning with "l."
* Examples: illegal, illogical, illiterate
Important Note: The prefixes "im-", "ir-", and "il-" all have the same basic meaning of "not." However, their usage is determined by the first letter of the word they attach to.