'Gash' is a term popular in English slang, it has a number of meanings, them being;
1. A wound, or cut.
2. Another word for vagina.
3. Slang for women/girls.
4. Adjective to describe something rubbish.
1. "I've got a gash on my face where I walked into that door"
2. "I was balls deep
in her gash"
3. "Mate, check out the fit gash at 3 o'clock"
4. "Can't you come? That's gash!"