Dic: second thought

1. N-SING : with brd-neg, a N
If you do something without a second thought, you do it without thinking about it carefully, usually because you do not have enough time or you do not care very much.

• This murderous lunatic could kill them both without a second thought.
• Roberto didn't give a second thought to borrowing $2,000 from him.

2. N-PLURAL : oft N about n
If you have second thoughts about a decision that you have made, you begin to doubt whether it was the best thing to do.

• I had never had second thoughts about my decision to leave the company.

3. PHRASE : PHR with cl
You can say on second thoughts or on second thought when you suddenly change your mind about [:]
(1) something that you are saying or
(2) something that you have decided to do.

• 'Wait there!' Kathryn rose. `No, on second thought, follow me.'

... Cobuild