negative prefix for 'rational'
irrational
negative prefix for 'legible'
illegible
negative prefix for 'common'
uncommon
negative prefix for 'paid'
unpaid
negative prefix for 'mature'
immature
negative prefix for 'rail'
derail
negative prefix for 'behave'
misbehave
negative prefix for 'spell'
misspell
negative prefix for 'expensive'
inexpensive
negative prefix for 'patient'
impatient
negative prefix for 'loyal'
disloyal