A Grimmie is an adult male who comes off as a nice guy but isn't actually a nice guy a.e. lecher, sadist, pervert etc.
Grimmie's attract or flock to younger females. Like Red Ridinghood and the big bad wolf. Grimmie's are known to have bad reputations with women. They are primarily characterized by their need for sex, sadistic attitudes and womanizing ways and their alluring prowess. Not to mention their distinguishing looks.
Her boyfriend's a Grimmie, he's a totally bastard and he's too old for her!