Spiteful, unkind.
Grave or dangerous (of an accident, illness etc.).
Contemptible, unpleasant (of a person).
Awkward, difficult to navigate; dangerous.
Dirty, filthy.
Indecent or offensive; obscene, lewd.
Formidable, terrific; wicked.
Objectionable, unpleasant (of a thing); repellent, offensive.
Sexual intercourse.
Something nasty.
A video nasty.
unfriendly
not congenial or compatible
not desiring the company of others
A person who is not sociable.