A girl who is cool, good friend, takes life seriously.
This word is most commonly used oppositely.
The word 'girl' is also interchangeable.
Girl1: Babe whats going on with you and Sarah?
Girl2: She screwed my brother.
Girl1: Oh my god she is NOT a serious girl!

Person1: MATE this sandwich tastes like crap
Person2: Its not a serious sandwich
by faloola2 May 29, 2009
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