This document lists prefixes that form opposites and provides examples of words using those prefixes. It includes the prefixes ir-, un-, il-, im- and in- and gives one or two word examples for each like illegal, immobil, irrational, unable and inaccurate that demonstrate how adding those prefixes changes the meaning.

1. Opposites with prefixes
Ir- Un-Il- Im-
Illegal
Illegible
Illiteral
Illogical
Immobil
Immoral
Imperfect
Impossible
Irrational
Irreconcilable
Irregular
Irresistible
In-
Unable
Uninteresting
Unusual
Uncomfortable
Unhelpful
Unprepared Inaccurate
Ineligible
Inorganic
Indecent
Insane