1.a webcommunity started by Missy Suicide, as a haven for the women of subcult to do artsy pin-ups. Peirced, tatooed, dyed and otherwise subculture girls coming together to take nude pictures. Recognized by playboy, Rolling Stones, and high end celebraties, its becoming a (somewhat) underground phenomena.
2. girls having, or trying to commit the act of suicide.
Suicide Girls definition by Urban Dictionary