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"adversary" is also used as a crossword clue. If that's what you saw, the answer is often opposer (7 letters).
Definitions
someone who offers opposition
Word origin
From Middle English adversarie, from Anglo-Norman aversaire (in Wace's Life of Saint Margaret) and Old French aversier, aversaire (French adversaire), from Latin adversārius, from adversus (“turned toward”). By surface analysis, adverse + -ary.
Used in a sentence
“He prepared to fight his adversary.”
“In the political drama that Donald Trump has created in Washington, he could not have dreamed up a more formidable adversary than James Comey.”
“Yahweh′s turning Gog around, putting hooks in his jaws, and bringing him out from the remotest parts of the north (Ezek. 38:4-6) is now interpreted as the release of the Adversary from prison.”
Source: Wiktionary, CC BY-SA 4.0
Used as a crossword answer1 curated clues
01“Opposing rival”9 letters
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