The term 'confessional topic' can be summarized as a discussion about one's sins or wrongdoings. The crossword solution for this term is SIN, which is an acronym for 'short for 'SINFUL''. SIN is a religious concept that refers to an action that goes against the teachings of a particular faith. It is often seen as a violation of God's will and can lead to spiritual consequences. Confessional topics are conversations that involve discussing one's sins and seeking forgiveness from God.