Congrats is a term used to sarcastically
congratulate someone on an
achievement, such as
atrocious behavior, a hideous style of clothing, or the amount of likes someone receives on an Instagram or Facebook photo which they probably paid people to like. "Congrats" is another way of telling someone that they are a fuck.
Example:
Girl 1: I'm having a party, but you're not invited.
Girl 2: Congrats!
*Girl walks by in high-waisted shorts*
Guy: Congrats on your high-waisted shorts that don't even
cover your ass!
*
Scrolling through a girl's Instagram or Facebook
newsfeed*
Girl 1: Congrats on your 100 likes on your photo!
Girl 2: Congrats on your pounds of makeup!