Sardonic

Definition: sarcastic, scornful, mocking

It sounds kind of like sarcastic, but the difference is that sardonic implies an attempt to belittle or mock someone, while someone could be sarcastic just for general humor value. Sardonic has a “meaner” edge to it than sarcastic.

Why I Looked It Up

From an H.P. Lovecraft short story:

Distant though the island was, he felt that a monstrous and invincible evil could flow from the sardonic stare of that bent, ancient figure in brown.