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Τὰ πάντα ῥεῖ καὶ οὐδὲν μένει → Everything flows and nothing stands still
heedless: P. and V. ῥᾴθυμος.
off one's guard: P. and V. ἀφύλακτος, ἄφρακτος.
rude: Ar. and P. ἄγροικος; see forgetful.