Nasty/ˈnæsti/ Definition 1 of 4Pro Tip 1/3Negative Feeling Implies strong dislike or disgust associated with something. The nasty taste of spoiled milk made me gag. Pro Tip 2/3Avoid in Formality Considered informal, use more neutral language in formal writing or speech. This substance has a nasty smell. Pro Tip 3/3Intensity Often used to intensify just how bad something is. They left the kitchen in a nasty state after cooking.