| second thought | |
| —n | |
| (usually plural) a revised opinion or idea on a matter already considered | |
| a screen or mat covered with a dark material for shielding a camera lens from excess light or glare. |
| a fool or simpleton; ninny. |
on second thought
Resulting from a revised opinion or change of mind, as in I thought I'd go to the movies, but on second thought I'd rather stay home. Similarly, have second thoughts means "change one's mind," as in I've had second thoughts about moving to Florida. This idiom alludes to ideas that come later. [Mid-1600s]