Extended Strong's Greek Lexicon (Abbott-Smith based)
be foolish
Usage: μωραίνω (μωρός), [in LXX: Isa.19:11, Jer.10:14 51:17 (בָּעַר ni.), 2Ki.24:10, Isa.44:25 R (שָׂכַל ni., pi.)* ;] __1. cl., to be foolish, play the fool. __2. LXX and NT, causal, to make foolish: 1Co.1:20; pass., to become foolish: Rom.1:22; of salt that has lost its flavour, become tasteless: Mat.5:13, Luk.14:34.† (AS)