gongusmos

This is a sound-word: the Greek name imitates the low, droning buzz of people muttering under their breath, the way English "murmur" or "grumble" half-echoes the noise it describes. At its plainest it simply means talk kept low, spoken to one another rather than out loud, and the surrounding scene decides whether that undertone is angry, fearful, or merely divided.

Almost every time the word carries the weight it does, though, it points back to one story: Israel complaining against Moses and against God in the desert. The Greek Old Testament used this word-group again and again for that wilderness murmuring, where the people's discontent with God's provision counted as outright rebellion. Once that link was forged, the word could evoke a whole role, the ungrateful crowd resenting the very gift it had been given, and New Testament writers reach for it precisely to sound that echo.

So the word runs across two registers. In one it is neutral: the whispered back-and-forth of a crowd that cannot make up its mind. In the other it is a charged word for resentful, half-hidden complaint against leaders or against God, the discontent that eats away at a community from underneath. The related word for open argument (διαλογισμός) names the wrangling out loud; this word names the discontent muttered quietly, and the Hebrew wilderness word it translates (תְּלֻנָּה) is what gives it its sting.