the.com/non sequitur

means A statement or conclusion that doesn't logically follow from what came before it.

from Straight from Latin: non ('not') plus sequitur ('it follows'), from sequi ('to follow') — the same root that gives us 'sequence' and 'sequel.' Originally a term of formal logic, naming a flawed syllogism whose conclusion doesn't actually follow from its premises. It later wandered out of the logic textbooks into everyday speech, where it now describes any remark that veers wildly off-topic, as if the conversation took a left turn no one signaled.