hindsight

noun

1. (countable, uncountable)Realization or understanding of the significance and nature of events after they have occurred.

   “You know what they say, hindsight is twenty-twenty.”

   “In hindsight, I realize that I should have studied harder for the exam.”

   “Hindsight is more easily acquired than foresight.”

2. (countable, rare, uncountable)The rear sight of a firearm.

   “Holonym: iron sights”