- Often second thoughts. reservation about a previous action, position, decision, judgment, or the like: He had second thoughts about his decision.
- on second thought, after reconsideration: On second thought, I don't think I'll go.
Origin of second thought
- (usually plural) a revised opinion or idea on a matter already considered
on second thought
Resulting from a revised opinion or change of mind, as in I thought I'd go to the movies, but on second thought I'd rather stay home. Similarly, have second thoughts means “change one's mind,” as in I've had second thoughts about moving to Florida. This idiom alludes to ideas that come later. [Mid-1600s]