Green’s Dictionary of Slang

1. unfortunate.

1965		(con. 1944) E.M. Nathanson Dirty Dozen (2002) 25: They figured him for another guard with a tough-shit assignment.
1984		W. Diehl Hooligans (2003) 17: It’s a tough-sheiss situation for him.
2000		N. Barlay Crumple Zone 146: Any stairwell’s his rehearsal studio, and any sad loser in earshot’s his tough shit audience.

2. essential, basic.

1971

B. Malamud Tenants (1972) 121: I ain’t gon work on your mama and sister which is the way we do it, but come right to the tough-shit funk of it, special for you.