To take one’s measure.

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1890.  In his rough vernacular, he wanted to “size him up,” and see if he was really soldier enough for him to “foller.”—Mrs. Custer, ‘Following the Guidon,’ p. 28 (N.Y.).

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1909.  He sized up Hezekiah, and seemed to know what was passing in his mind.—The Judge, Feb. (N.Y.).

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