en_tn_condensed/pro/26/05.md

Answer a fool and join in on his folly

Joining in on a fool's folly when answering him represents answering him in a foolish way. Alternate translation: "Answer a fool according to his folly" or "Answer a fool foolishly"

so he will not become wise in his own eyes

The eyes represent seeing, and seeing represents thoughts or judgment. Alternate translation: "so that he will not become wise according to his judgement" or "so that he does not consider himself to be wise" (See: rc://en/ta/man/jit/figs-metaphor)