Any woman in a relationship (usually marriage) with a man having one or more children from his last partnership. As far as getting along with dads new mate some step-kid's do and some step-kid's don't. Bottom line is that this woman wants to be with the guy so much that she is willing to step-up to the situation.

A woman whom has stepped into your life without caution and once she's been fucking around with your dad for about 2 weeks she thinks she owns him and wants you out of the picture. Basically, a fucking step mom is a wannabe mom, bitch, whore and someone who wants YOU out of the picture, and this cunt always gets her way...