1. A girl who is inactive during sex.
2. A girl who is hard to get into bed.
"Fuck, I'm banging away missionary for like 40 minutes with this tin soldier broad..."
"You're better to drunk dial, this chick is a tin soldier."
A Soldier without a metaphorical Heart; a goon. Origins in the Wizard of Oz character of the same name tied with the reality of the shooting of unarmed college students by the Ohio National Guard during the Kent State shootings; Coined in this alloy by Neil Young in the song 'Ohio:'
"Tin soldiers and Nixon coming, We're finally on our own. This summer I hear the drumming. Four dead in Ohio."