A person who strongly dislikes or is opposed to someone or something, or in modern slang, someone who criticizes you out of jealousy.
From 'hate' plus '-er,' a straightforward formation; the modern slang meaning ('haters gonna hate') became popular in hip-hop and pop culture in the 2000s.
The word 'hater' exploded in the 2000s when celebrities needed to dismiss critics as jealous—it flipped the meaning from someone with legitimate disagreement to someone whose opinion doesn't deserve attention!
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