Short for "
represent." So... "represent it." As in...
promote what you do, what you are, what you love,
whatever affiliation you're apart of.
"I freaking love this weird
subgenre of music, but none of my friends are into it."
"
Whatever man...
rep it. Do you."
"I am a part of this kickass group on Facebook."
*takes a picture of self representing it/being a part of it"
Caption: "
Rep it."
*Has picture of self doing a hobby and looking badass*
Friend's response: "Rep it!"