κενόω, -ῶ

(κενός, which see), [in LXX: Jer.14:2 15:9 (עָמָל pu.)* ;]

to empty. Metaphorical, to empty, make empty, vain or of no effect: καύχημα, 1Co.9:15; ἑαυτόν, of Christ, Php.2:7 (v Lft.; ICC, in 1, and esp. Gifford, Incarn. 54 ff.); pass. πίστις, Rom.4:14; ὁ σταυρός, 1Co.1:17; καύχημα, 2Co.9:3†

(AS)

to empty; make empty; vain; of no effect