look up any word, like the eiffel tower:
 
1.
The exact opposite of a butter face. A girl who has a great face but not a good body.
I diagnosed myself with I can't believe it's not butter! I so need to start working out!
by Kaydaymuchluv81 December 01, 2011
 
2.
is when you see an ugly person that has some how made themself look attractive through clothes, make-up or other non-plastic surgery enhancement. To test this on someone after a few cocktails (less than three) consider if you would park the love rod in the ham wallet. If yes: "I can't beleive its not butter!" - if no: see fugly.
"Wow, have you seen what Sally is wearing? She's sort of cute now."

Yeah, I know! I can't believe it's not butter!
by prosebrosproductions June 17, 2010
 
3.
Insult used with somebody's name, used if the person has man boobs
"Whoa, you see that guy's man boobs?"

"Yeah, I can't believe it's not butter"
by The Teacher, PhD in swearing July 15, 2009
 
4.
when you cum on a girls back and or bread then spread with a butter knife. She then eats the bread on her back you lie down on her back and you get stuck to her.
i did a i cant believe its not butter to my girl last nite.
by tkifr March 02, 2008