1
Legal
Illegal
Responsible
Irresponsible
Possible
Impossible
Regular
Irregular
Logical
Illogical
Legible
Illegible
Probable
Improbable
Patient
Impatient
Reconcilable
Irreconcilable
Perfect
Imperfect
Usual
Unusual
Rational
Irrational
Literate
Illiterate
Practical
Impractical
Relevant
Irrelevant
Correct
Incorrect
Happy
Unhappy
Official
Unofficial
Visible
Invisible
Formal
Informal
Mortal
Immortal
Active
Inactive
Successful
Unsuccessful
Real
Unreal
Friendly
Unfriendly