nastiest
nas-ti-est
adjective
The superlative form of 'nasty', meaning most unpleasant, unkind, or offensive.
"That was the nastiest comment I've ever heard."
Thesaurus
Synonyms: foul, nasty, dirty, filthy, smutty, cruddy, mean, grotty, hateful, lousy, awful, hard
Antonyms: nice