nasty vs unfriendly

nasty

• 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

• Unfavourable. 

• Not friendly; hostile; mean. 

• An enemy. 

• in an unkind or unfriendly manner; not as a friend