The noun conviction means a strong belief or a strong feeling of being certain about something. The noun conviction also means the case of officially being found to be guilty of a particular crime.
Synonyms are confidence, faith, feeling, or principle.
The word origins from Late Latin (mid 15th century) convictionem meaning “proof, refutation”, noun of action from past-participle stem of convincere meaning “to overcome decisively”. It comes from com-, here probably an intensive prefix (see com-), plus vincere meaning “to conquer”.
There was a conviction for slavery.
His conviction was clearly seen on his face.
Ronald’s statement lacked conviction.