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1.
Insulting; devaluing; or belittling oneself, often in a sarcastic or humorous way.
Young girls are so self deprecating. They never talk about anything but their flaws.

Tate: I have to cancel our plans this weekend!
Lana: Don't worry about it; I'm an expert when it comes to spending weekends alone.
Tate: You're so self deprecating sometimes, Lana.
by Kellyisawin! December 02, 2013