ἄφωνοςáphōnos

voiceless, i.e. mute (by nature or choice); figuratively, unmeaning

Greek (New Testament) · G880

Meanings

dumb, speechless: Acts 8:32(LXX); of idols, 1 Corinthians 12:2; of beasts, 2 Peter 2:19; τοσαῦτα γένη φωνῶν καὶ οὐδὲν ἄ.—so many kinds of voices and none voiceless, i.e. without signification, unintelligible: 1 Corinthians 14:10.

Same root

ΑA · G1the first letter of the alphabet; figuratively, only (from its use as a numeral) the first:
φωνήphōnḗ · G5456a tone (articulate, bestial or artificial); by implication, an address (for any purpose), saying or language

Where it appears

Appears 4 times in the Bible.

Acts 8:32 The passage of Scripture he had been reading was this: “He was led like a sheep to the slaughter. And as a lamb is silent before the shearers, he did not open his mouth.
1 Corinthians 12:2 You know that when you were still pagans, you were led astray and swept along in worshiping speechless idols.
1 Corinthians 14:10 There are many different languages in the world, and every language has meaning.
2 Peter 2:16 But Balaam was stopped from his mad course when his donkey rebuked him with a human voice.

Source: G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922), public domain.