ψύχωpsýchōStrong's G5594

to breathe (voluntarily but gently, thus differing on the one hand from G4154, which denotes properly a forcible respiration; and on the other from the base of G109, which refers properly to an inanimate breeze), i.e. (by implication, of reduction of temperature by evaporation) to chill (figuratively)

Derivation: a primary verb