a second thought

a second thought

A pause for a second or further consideration; a hesitation or concern about (doing) something. It isn't worth a second thought at this stage. When we were kids, we never gave a second thought about whether this food or that was good for us—we tried to eat what tasted good, and tried to avoid what tasted bad.
See also: second, thought
Farlex Dictionary of Idioms.

a second thought

a moment's further consideration; any worry or concern.
See also: second, thought
Farlex Partner Idioms Dictionary
See also:
  • in (just) a second
  • in a second
  • any second now
  • any second
  • second bite of the apple
  • second go
  • number two
  • your/somebody's number two
  • wait a second
  • second fiddle