Observant

a.	1.	Taking notice; viewing or noticing attentively; watchful; carefully attentive; as, an observant spectator; observant habits. Wandering from clime to clime observant stray'd. - Pope.
	2.	Submissively attentive; obediently watchful; regardful; mindful; obedient (to); - with of, as, to be observant of rules. We are told how observant Alexander was of his master Aristotle. - Sir K. Digby.
n.	1.	One who observes forms and rules.
	2.	A sycophantic servant. Silly ducking observants, That stretch their duties nicely. - Shak.
	3.	(R. C. Ch.) An Observantine.

Adj.	1.	observant - paying close attention especially to details
	2.	observant - quick to notice; showing quick and keen perception Synonyms: observing
	3.	observant - (of individuals) adhering strictly to laws and rules and customs; "law-abiding citizens"; "observant of the speed limit" Synonyms: law-abiding

Argus-eyed, active, advertent, agog, all ears, all eyes, assiduous, aux aguets, awake, compliant, concentrated, conforming, conscientious, constant, custodial, deferential, devoted, devout, diligent, duteous, dutiful, eagle-eyed, earnest, ethical, faithful, finical, finicking, finicky, guarded, hawk-eyed, intense, intent, intentive, keen, keen-eyed, lidless, loyal, meticulous, moral, nice, niggling, obedient, observing, on guard, on the ball, on the job, on the lookout, on the watch, open-eared, open-eyed, openmouthed, perceptive, practicing, prudent, punctilious, punctual, regardful, respectful, scrupulous, sharp, sharp-eyed, shrewd, sleepless, thoughtful, true, vigilant, wary, wide awake, with open eyes