1. Most popularly used as an interjection without the stigma of sexual inappropriateness with words such as fuck
2. To move one's bowels, to eliminate.
3. One's less valued personal possessions, most commonly used to describe debatably useless junk, drugs (ie good shit).
1. Shit! Shit shit shit shit shit shit!
2. I just shat on a truly monstrous magnitude.
3. Why doesn't he just pick this shit up?