To hand wash is to wash clothes gently by hand rather than by machine. Hand wash only, hand wash in cool water, must be hand washed.
Hand wash only on a label means the fibres will felt or the shape will go in a machine, which is true of wool above all. Squeezing rather than wringing is the whole technique.
1phrasehand washTo wash clothes gently by hand, not by machine.
“You should hand wash this wool jumper in cool water.”
hand wash is a washing.
Hand plus wash, from Old English wascan, to wash, and hand, both among the oldest words in the language.
From hand + wash.
Etymology from Wiktionary, CC BY-SA
Practised in Cleaning & Housework