When you picture anger, it evokes a physical response; when anguish, an emotional response; when despair, a spiritual response. This word, when used as a phrase, evokes all three responses.
A good replacement for "That sucks, bro."
"Man, I have to work 1-12 tomorrow."
"That's punishing"
"Dude I totally punished that final exam"
"Oh my god the new Nicki Minaj song is punishing."