Green’s Dictionary of Slang

harsh adj.

1. (US campus/teen) very unpleasant, exceptionally rude, ill-mannered, extremely bad.

[US]Eble Campus Sl. Oct. 3: harsh – difficult: Living with Linda is harsh.
[US]A. Heckerling Clueless [film script] tai: You don’t think that we mesh well? It is like, why am I even listening to you to begin with? You’re a virgin who can’t drive (Cher is brought to the point of tears. You bitch, Tai!!!) cher: That was way harsh, Tai.
[US]Eble Campus Sl. Nov.

2. (US drugs) used of marijuana that, whether through strength or dryness, makes one cough.

[US]ONDCP Street Terms 11: Harsh — Marijuana.