expression, noun
something unrelated; a different matter
Used to introduce a question or topic that is unrelated to the current conversation. Often appears in the set phrase つかぬことを伺いますが (Excuse me for asking something unrelated, but...).
つかぬことを伺いますが、お名前は何とおっしゃいますか。
Excuse me for asking something unrelated, but what is your name?
会議中につかぬことを言ってしまった。
I ended up saying something unrelated during the meeting.
唐突 means 'abrupt' or 'sudden', focusing on the unexpectedness of a statement or action, while つかぬ事 specifically refers to a topic that is unrelated to the current discussion.
The phrase つかぬ事 is composed of the negative form of the verb 付く (つく, 'to be attached') and 事 (こと, 'thing'), literally meaning 'a thing not attached' to the current topic. The exact historical derivation is uncertain, but it is conventionally used to refer to an unrelated matter.