believe
disbelieve = verb
disbelief = noun
unbelievable = adjective
legal
illegal
responsible
irresponsible
please
unpleasant
mature
immature
educated
uneducated
likely
unlikely
honest
dishonest
aware
unaware
literate
illiterate
careful
careless
harmful
harmless
able
unable ‘ the exercise is too difficult. I was unable to do it’
disable
expected
unexpected
capable
incapable
efficient
inefficient
faithful
unfaithful
known
unknown
greatful
ungreatful
contented
discontented
fair
unfair