Lexical Definition

‎ἀῤῥαβών‎ arrhabṓn (ar-hrab-ohn') guarantee ^G:N-M
of Hebrew origin (‎עֲרָבוֹן‎)

earnest.

• a pledge, i.e. part of the purchase-money or property given in advance as security for the rest

Abbott-Smith

ἀρραβών (T, ἀραβ-: II Co 1:22 5:5), -ώνος, ὁ, [in LXX: Ge 38:17, 18, 20 (עֵרָבוֹן)*;]
an earnest, part payment in advance for security, a first instalment: II Co 1:22 5:5, Eph 1:14. (The word is found in cl. and was prob. brought to Greece by the Phœnicians (AR, Eph., 1:14). It is found in π. with both spellings (v. Milligan, NTD, 73). In MGr. ἀρραβῶνα is an engagement ring; v. MM, s.v.)†

Abbott-Smith References

Liddell-Scott-Jones

ἀρραβών, ῶνος, ὁ,

earnest-money, caution-money, deposited by the purchaser and forfeited if the purchase is not completed, ἀ. δοῦναί τινος[Refs 4th c.BC+]: plural, deposits required from public contractors, [Refs]

__2 generally, pledge, earnest, τὴν τέχνην ἔχοντες ἀ. τοῦ ζῆν[NT+4th c.BC+]
__3 present, bribe, [Refs 1st c.AD+]. (Semitic, probably Phoenician, word, Hebrew 'ērābōn: frequently written ἀραβών, [NT+2nd c.BC+]
__II ἀρραβών· πρόδομα, καὶ ἄγκιστρον, [Refs 5th c.AD+]

_{LSJ Scripture Refs: LXX.Gen.38.17 ☩ Eph.1.14}