Extended Strong's Greek Lexicon (Abbott-Smith based)
to murmur
Usage: γογγύζω, [in LXX chiefly for לוּן ;] to mutter, murmur: 1Co.10:10; before κατά, Mat.20:11; πρός, Luk.5:30; περί, Jhn.6:41, 61; μετ᾽ ἀλλήλων, Jhn.6:43; with accusative, before περί, Jhn.7:32 (cf. δια-γογγύζω).† (AS)