Some critics say the Hebrew word "תם" (tam) should not be translated "plain" because the word means "perfect", "complete", "morally innocent" or "having integrity" (Brown-Driver-Briggs’ Hebrew Definitions). However, the word also means "an ordinary, quiet sort of person" (Brown-Driver-Briggs’ Hebrew Definitions). Such a person is a "plain man". Some other translations convey the same sense as the KJV rendering:
Context-wise, Genesis 25:27 would not make sense unless the word is translated into English conveying the nuance of being plain. The verse makes a connection between Jacob's inner trait and his outer appearance as a person dwelling in a tent. The act of dwelling in a tent is not indicative of moral uprightness but it is indicative of plainness.
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