n., v., & adj.
n. 1 a an area of shallow water. b a submerged sandbank visible at low water. 2 (esp. in pl.) hidden danger or difficulty.
v. 1 intr. (of water) get shallower. 2 tr. (of a ship etc.) move into a shallower part of (water).
adj. archaic (of water) shallow. shoaly adj.
[ OE sceald f. Gmc, rel. to SHALLOW ]