Synonyms and related words :
accountability, ambuscade, ambush, ambushment, auspices, blind, booby trap, bossing, bugging, care, charge, cloak-and-dagger work, counterespionage, counterintelligence, custodianship, custody, eagle eye, electronic surveillance, espial, espionage, eye, following, guard, guardedness, guardianship, intelligence, intelligence work, intendance, invigilation, jurisdiction, lookout, lurking hole, military intelligence, monitoring, observance, observation, oversight, peeled eye, proctoring, prudence, qui vive, reconnaissance, responsibility, scrutiny, secret police, secret service, shadowing, sharp eye, spying, stakeout, stalking-horse, stewardship, superintendence, supervision, tab, tailing, tout, trailing, trap, vigil, vigilance, wariness, watch, watch and ward, watchful eye, watchfulness, watching, weather eye, wiretap, wiretapping