sb. [f. prec. + -ANT1, after stimulant, etc.] A counteracting agency or force.

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1884.  Pall Mall Gaz., 5 Dec., 3/1. [This] is the best possible counteractant of the disloyal utterances.

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1891.  C. Waldstein, in Harper’s Mag., April, 752/1. It is a great rectifier of style and counteractant to mannerism.

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