Dictionary
sec'ond thought'
1. Often,
second thoughts. reservation about a previous action, position, decision, judgment, or the like:
He had second thoughts about his decision.
2. on second thought, after reconsideration:
On second thought, I don't think I'll go. Also,sec'ond-thought'.Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.