Second thought is defined as a reconsideration of something or a change in mind.
When you first decide to paint a room white and then you think about it some more and decide to paint it blue, this reconsideration and mind change is an example of a second thought.
a change in thought about a matter after reconsidering it
second thought Idioms
on second thought
A reconsideration of a decision or opinion previously made.
- Alternative spelling of second thoughts.