ἀπολούωapoloúō

to wash fully, i.e. (figuratively) have remitted (reflexively)

Greek (New Testament) · G628

Meanings

to wash off, wash away; middle, metaphorically, with accusative of thing, to wash off oneself: ἁμαρτίας, Acts 22:16; absolutely, ἀπελούσασθε, ye washed yourselves clean, 1 Corinthians 6:11.

Same root

ἀπόapó · G575"off," i.e. away (from something near), in various senses (of place, time, or relation; literal or figurative)
λούωloúō · G3068to bathe (the whole person; whereas G3538 (νίπτω) means to wet a part only, and G4150 (πλύνω) to wash, cleanse garments exclusively)

Where it appears

Appears 2 times in the Bible.

Acts 22:16 What are you waiting for? Get up and be baptized. Have your sins washed away by calling on the name of the Lord.’
1 Corinthians 6:11 Some of you were once like that. But you were cleansed; you were made holy; you were made right with God by calling on the name of the Lord Jesus Christ and by the Spirit of our God.

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