Putting someone or something in a less favorable position or situation; treating someone in a way that harms their chances of success.
Present participle of disadvantage (to put at a disadvantage), from dis- + advantage. This verbal form emerged as disadvantage became commonly used as a verb in English.
The shift of 'disadvantage' from purely a noun to an active verb shows how English constantly transforms words between parts of speech—you can now disadvantage someone, just as you can advantage them.
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