- Objectionable, unpleasant (of a thing); repellent, offensive. [from 16th c.]
- (chiefly Britain) Awkward, difficult to navigate; dangerous. [from 19th c.]
- Contemptible, unpleasant (of a person). [from 15th c.]
- Spiteful, unkind. [from 19th c.]
- (slang, chiefly US) Formidable, terrific; wicked. [from 20th c.]
- (now chiefly US) Dirty, filthy.
- Indecent or offensive; obscene, lewd. [from 17th c.]
- (chiefly Britain) Grave or dangerous (of an accident, illness etc.). [from 19th c.]
- (informal) Something nasty.
"Processed foods are full of aspartame and other nasties."
"This video game involves flying through a maze zapping various nasties."