COUNTENANCE (noun: פָּנִ֑ים, πρόσωπον, G4725, meaning “face,” are the most frequent. Verb: הָדַר, H2075, “to countenance”).
There are other and similar Heb. nouns which are often tr. “countenance,” and which literally denote such meanings as “shape,” “comeliness,” “visage,” “appearance.” The countenance, or face, mirrored the character of a person—and the thoughts of his heart. The countenance is “cheerful” (Prov 15:13), “angry” (25:23), “fierce” (Dan 8:23 KJV), “troubled” (Ezek 27:35 KJV).
The RSV does not have the verbal “to countenance” in Exodus 23:3 as the KJV does, but instead has “be partial”: “nor shall you be partial to a poor man....” (Justice is to be unbiased to such an extent that not even the poor man is to be favored.) See Face.
International Standard Bible Encyclopedia (1915)
(2) As verb (Hebrew hadhar, "to countenance") we find the word in the King James Version of Ex 23:3, where the Revisers translate "Neither shalt thou favor (the King James Version "countenance") a poor man in his cause." Here the meaning seems to be that no distinction of persons shall be made by the judge. See Le 19:15, where, however, a different word is used. There is therefore no need of the emendation proposed by Knobel and accepted by Kautzsch, who would read gadhol, "great," for wedhal, "and the poor" of the text. The Septuagint has penes, "poor."