*Twah-

from Møller:

Gothic 'Twahan', OHGG 'dwahan', OE 'Twe:an', ON 'Twa:'
(Dan. 'to:' "abluere, wash clean, wash away",
Gothic 'Twahl', OHG 'dwahal' "bath"
OHG 'dwahilla', 'dwehila', German 'zwehle', 'quehle' "washing cloth,
towel",
OPruss 'twaxtan' "bathing sponge"

Hebr d-w-H- "abspülen (den Altar, die Blutschuld)"



If it's a loan it would be interesting to know whether it was
borrowed with the religious/legal significance. 'Twahan' is strictly
about cleaning the body, not clothes (which is where 'wash' comes
in). Elsewhere in IE, cleaning both in the literal and figurative
sense is *lu- (AFAIK), but in Germanic that root is still used in
the figurative sense.

Torsten