civility
The definition for civility is "Politeness." Used in a sentence: The usually unruly Thomas acted with great civility when his favorite uncle visited.
dubious
The definition for dubious is "Questionable." Used in a sentence: Karl found Kevin's claim that he was sick dubious, as he had just seen him playing football.
genial
The definition for genial is "Sympathetic, friendly." Used in a sentence: The genial host warmly greeted his many guests.
impenitent
The definition for impenitent is "Lacking remorse." Used in a sentence: The impenitent criminal received a harsh penalty, but his remorseful accomplice was released.
periodic
The definition for periodic is "Occurring at regular intervals." Used in a sentence: The periodic innterruptions of the cuckoo clock prevented Li from concentrating.