n. & v.
n. (pl. spies) 1 a person who secretly collects and reports information on the activities, movements, etc., of an enemy, competitor, etc. 2 a person who keeps watch on others, esp. furtively.
v. (spies, spied) 1 tr. discern or make out, esp. by careful observation (spied a house in the distance). 2 intr. (often foll. by on) act as a spy, keep a close and secret watch. 3 intr. (often foll. by into) pry. I spy a children's game of guessing a visible object from the initial letter of its name. spy-master colloq. the head of an organization of spies. spy out explore or discover, esp. secretly.
[ ME f. OF espie espying, espier espy f. Gmc ]