FROM STRONG’S GREEK DICTIONARY (1890)

Strong’s Greek Dictionary (1890) — public domain, printed whole.

arrhetos ἄρρητος — ar'-hray-tos — from 1 (as a negative particle) and the same as 4490; unsaid, i.e. (by implication) inexpressible:--unspeakable.

see GREEK for 1

see GREEK for 4490