The Collaborative International Dictionary of English v.0.48:

Sallow \Sal"low\, a. [Compar. Sallower; superl. Sallowest.]
   [AS. salu; akin to D. zaluw, OHG. salo, Icel. s["o]lr
   yellow.]
   Having a yellowish color; of a pale, sickly color, tinged
   with yellow; as, a sallow skin. --Shak.
   [1913 Webster]