1.
to become threatening and violent :
You'd better do what he says or he'll turn nasty.
2.
to become bad or unpleasant :
It looks as though the weather is going to turn nasty again.
1.
to become threatening and violent :
You'd better do what he says or he'll turn nasty.
2.
to become bad or unpleasant :
It looks as though the weather is going to turn nasty again.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005