devilish

devilish is an   Adverb

Definition:

[1] Resembling, characteristic of, or pertaining to, the devil; diabolical; wicked in the extreme. "Devilish wickedness." Sir P. Sidney. This wisdom descendeth not from above, but is earthly, sensual, devilish. James iii. 15.

[2] Extreme; excessive. [Colloq.] Dryden.

Synonyms: