Lexical Definition

‎βάρβαρος‎ bárbaros (bar'-bar-os) barbarian G:A
of uncertain derivation

barbarian(-rous).

Usage: 5 forms in 8 verses
Form Translated As     In Verse(s)
βαρβάρων of barbaric LXX.Ezek.21.31
βαρβάρου a barbaric LXX.Ps.114.1
βαρβάροισ to barbarians Rom.1.14
βάρβαροσ Barbarian Col.3.11
a foreigner 1Cor.14.111Cor.14.11
βάρβαροι natives Acts.28.4
the natives Acts.28.2

Abbott-Smith

βάρβαρος, -ον (prob. onomatop., descriptive of unintelligible sounds), [in LXX: Ps 113 (114):1* (לעז), Ez 21:31* (36*) (בּער), II Mac 2:21 4:25 10:4, III Mac 3:24*;]
barbarous, barbarian, strange to Greek language and culture (and also, after the Persian war, with the added sense of brutal, rude): Ac 28:2, 4, Ro 1:14, I Co 14:11, Col 3:11 (v. Lft., in l., and Notes, 249).†

Abbott-Smith References

Book Refs
Psalms 114:1*
Ezekiel 21:31* · 21:36*
Acts 28:2 · 28:4
Romans 1:14
1 Corinthians 14:11
Colossians 3:11

Liddell-Scott-Jones

βάρβαρος, ον,

barbarous, i.e. non-Greek, foreign, not in [Refs 8th c.BC+]; especially as substantive βάρβαροι, οἱ, originally all non-Greek-speaking peoples, then specially of the Medes and Persians, [Refs 5th c.BC+]; β. πόλεμον war with the barbarians, [Refs 5th c.BC+]; βάρβαρος (i.e. γῆ), opposed to αἱ Ἑλληνίδες πόλεις, [Refs 5th c.BC+] adverb -ρως, opposed to Ἑλληνικῶς,[Refs 3rd c.AD+]

__2 especially of language, φωνὴ β. [Refs 5th c.BC+]; συλλραφαί[Refs 4th c.BC+]; of birds, [Refs 5th c.BC+] adverb, βαρβάρως, ὠνόμασται have foreign names, [Refs 1st c.BC+]
__3 Grammars, of bad Greek, [Refs 2nd c.AD+]; τὸ β., of style, opposed to Ἑλληνικόν, [Refs 2nd c.AD+]
__II after the Persian war, brutal, rude, ἀμαθὴς καὶ β. [Refs 5th c.BC+]: comparative -ώτερος[Refs 5th c.BC+] Eph.2.4: superlative, πάντων βαρβαρώτατος θεῶν [Refs 5th c.BC+]
__III used by Jews of Greeks, [LXX]
__IV name for various plasters, [Refs 1st c.BC+]