without a second thought

Meaning

1. immediately; without stopping to think about sth further

   He dived in after her without a second thought.

From the same entry

• have second thoughts
• on second thoughts
• collect yourself thoughts
• food for thought
• give pause
• a penny for your thoughts
• perish the thought
• school of thought
• a train of thought
• the wish is father to the thought
• come to think of it
• I don't think so