Third person singular present tense of 'cleave': splits or cuts something into parts, or (archaic) sticks closely to something.
From Old English 'cleofan' (to split). The verb 'cleaves' maintains its original form from Anglo-Saxon times and is still used in modern English, though it can be ambiguous given the two opposite meanings.
Medieval butchers would say 'the cleaver cleaves the meat'—using the same word in two ways (the tool and the action) because they share the same root. Language sometimes has fun with these punny patterns.
Complete word intelligence in one call. Free tier — 50 lookups/day.