arrhes

There are two words spelled 'earnest' in English, and they have nothing to do with each other. The adjective earnest (meaning serious, sincere) comes from Old English eornoste, a Germanic word. The noun earnest (meaning a deposit or pledge) comes from Old French arrhes, which came from Latin arrha, which came from Greek arrabōn (ἀρραβών), which came from Hebrew ʿērāḇōn (עֵרָבוֹן).

The Hebrew word appears in Genesis 38:17-18, where Judah gives Tamar his seal, cord, and staff as an ʿērāḇōn—a pledge guaranteeing future payment. The word traveled from Hebrew to Phoenician traders, then to Greek merchants, then to Roman law, where arrha became a standard legal term for a deposit binding a contract.

Old French arrhes entered English as ernes or ernest in the 1200s, gradually merging in spelling with the native adjective earnest. The collision was accidental but poetically apt: earnest money is money paid in earnest. The Hebrew pledge and the Germanic sincerity fused into a single spelling by the 1500s.

Modern real estate still uses earnest money—a deposit proving the buyer's serious intent to purchase. Typical earnest money deposits range from 1 to 3 percent of the home price. If the buyer backs out without cause, they forfeit the earnest. The word still works exactly as it did in Genesis: a tangible guarantee of a promise not yet fulfilled.