gotcha

Short definition from Wiktionary

Contraction

1. 1
   Pronunciation spelling of got you.

Interjection

1. 1
   I have got you covered, I've got your back (said by a speaker who has an advantage or responsibility over someone).
2. 2
   I caught you (as when successfully bringing someone to reckoning or effecting some form of retribution).
3. 3
   I got you by surprise (indicating a successful trick or prank).
4. 4
   I understand you or what you said.

Noun

1. 1
   A potential problem or source of trouble.
2. 2
   A potential problem or source of trouble: A feature of a system or a program that works in the way it is documented but is counter-intuitive and almost invites mistake or non-function.
3. 3
   An instance of publicly tricking someone or exposing them to ridicule, especially by means of an elaborate deception.
4. 4
   An attempt to disprove or refute someone's argument, usually (but not necessarily) in a deceptive or disingenuous way.
5. 5
   An instance of accomplishing a tricky idea or overcoming a difficult obstacle.