- of, like, or suitable to hell; infernal; vile; horrible: It was a hellish war.
- miserable; abominable; execrable: We had a hellish time getting through traffic.
- devilishly bad: The child’s behavior was hellish most of the day.
- of or resembling hell
- wicked; cruel
- informal very difficult or unpleasant
- British informal (intensifier)a hellish good idea
1520s, from hell + -ish. Related: Hellishly; hellishness. Earlier in same sense were helli “helly” (late 12c.); hellen “hellish, infernal” (c.1200), with -en (2); and Old English hellic.