watch

observer, patrol, spotter, surveillant, watchdog

bodyguard, convoy, defender, escort, honor guard

gatekeeper

hack [slang]

aliveness, awareness, consciousness, mindfulness, receptiveness, receptivity, sensitivity

care, carefulness, cautiousness, chariness, heedfulness, wariness

preparation, readiness

observance, observation, supervision

inspection, scrutiny

behold, look, perceive, regard, see, view

gape, gawk, gaze, glare, goggle, look on, peer, rubberneck, stare

guard, wake, ward

bird-dog, monitor, study

spy

espy, glance, glimpse, peek, peep

consider, contemplate, mull, ponder, weigh

comply (with), conform (to), keep, obey, respect

attend (to), hark (to), hear, hearken (to)

mark, notice, see

surveil

eye

behold, espy, look, note, notice, observe, regard, see, sight, spy, view, witness

gape, gawk, gaze, glare, goggle, peer, rubberneck, stare

glance, glimpse, peek, peep

attend, heed, regard

note, notice, observe

empathize (with), feel (for), sympathize (with)

administrate, conduct, control, direct, govern, guide, manage, operate, preside (over), regulate, run, steward

guard, patrol, protect, safeguard, shield

baby, babysit, chaperone (or chaperon), mother, shepherd