γελᾷ δ' ὁ μωρός, κἄν τι μὴ γέλοιον ᾖ → the fool laughs even when there's nothing to laugh at
P. and V. εὔκοσμος, κόσμιος.
Use P. and V. κοσμεῖν, P. διακοσμεῖν.