noun

• (photography) Clipping of negative.
• (rhetoric) Clipping of negative.
• (seduction community) An expression or implication that one has a negative value judgement of someone in order to make them desire one's approval, especially when trying to pick up a date.
  "The purpose of a neg is to lower a woman's self esteem while actively displaying a lack of interest in her—by telling her she has lipstick on her teeth, for example, or offering her a piece of gum after she speaks."
• (quiz bowl) a penalty for giving an incorrect answer before a tossup has been fully read.

adj

• (LGBTQ slang) HIV negative.

verb

• (slang, British) To annoy or irritate deliberately.
• (transitive, seduction community) To express or imply a negative value judgement of someone to make them desire one's approval, especially when trying to pick up a date.
  "Women, on the other hand, are wired to believe that men are always ready to reach home base and never turn down a booty opportunity. So when he negs you, it seems unnatural, and you may worry that something’s wrong with your relationship."
• (transitive, Internet slang) To leave negative feedback about (someone) in a reputation tracking system.
  "I negged the seller who didn't send me the widget I paid for."

name

• (Australian politics) Initialism of National Energy Guarantee.