Prefixes un-, in-, im-, ir-, il-, dis- and mis-

Prefixes un-, in-, im-, ir-, il-, dis- and mis- are used to make negative forms: natural -> unnatural

popular. unpopular
human. inhuman
practical. impractical
musical. unmusical
understood. misunderstood
logical. illogical
regularly. irregularly
appear. disappear
consistently. inconsistetly
famous. infamous