Synonyms for Observe:

n.

adhere to, recognize, keep to. descry, formulate, pronounce on, sound off, speak out, air, mind, knowledge, express, articulate. awareness, fall, eye, make out, pick out. legacy, mores, local color, trick or treat, words, custom, tradition, practice, manners, institution. same, watch for, follow/watch someone's every move, keep (a) watch, be on the lookout for, spy on, stand over, carry out. remember. observe (noun)
find, note, honor, keep, watch over, watch, follow, mention, discover, take note, honour, abide by, maintain, remark, keep an eye on, respect, detect, notice.

v.

abide by, obey (verb)
adhere, conform, comply, follow, fulfill.
celebrate (verb)
memorialize, hail, carouse, revel, party, trumpet, hallow, frolic, glorify, exult, commemorate, make merry, celebrate, honor, jubilate, cheer, venerate, proclaim, salute, laud, praise, solemnize, inaugurate, acclaim, enjoy, rejoice, fete.
celebrate, commemorate (verb)
keep, honor, venerate, solemnize, remember, respect.
comment, remark (verb)
mention, state, opine, declare.
comply (verb)
assent, cede, consent, genuflect, submit, knuckle under, agree, succumb, cave, accept, bend, defer, fulfill, concur, respect, yield, kowtow, adhere, comply, bow, acquiesce, obey, capitulate, conform, surrender.
conform (verb)
ape, mimic.
evince (verb)
certify, document, avouch, exemplify, support, depose, declare, testify, betoken, indicate, illustrate, evince, state, manifest, confirm, demonstrate, attest, establish, connote, authenticate, adduce, determine, witness, vouch, exhibit, substantiate, validate, prove, corroborate.
examine (verb)
verify, scrutinize, study, peruse, review, examine, survey, scan, check.
imagine (verb)
create, invent, envision, fantasize, conceive, plan, brainstorm, ideate, design, think, consider, theorize, reflect, opine, imagine, suppose, contemplate.
observe (verb)
sight see, spectate, view, gaze, look, eyewitness, watch, perceive, behold.
see (verb)
glance, see, inspect, sight, peek, glimpse, regard, spy, stare, glare, discern, peer.
see, notice (verb)
perceive, regard, scrutinize, behold, study, make out, survey, inspect, recognize, witness, note, mind, contemplate, discern, view, spy, examine, detect, discover, watch.

Other synonyms:

mind, recognize, adhere to, keep to, pick out, watch for, stand over. spy on. fall. celebrate
make merry, glorify, laud.
comply
adhere to.
discover
descry, detect.
follow
keep an eye on.
heed
watch over.
look at
view, watch.
notice
notice.
obey
obey.
see
sight.

Usage examples for observe

  1. He stopped to observe the effect of his reply. – Man and Wife by Wilkie Collins
  2. Burns may triumph over his world, often he does triumph over his world, but let us observe how and where. – Selections from the Prose Works of Matthew Arnold by Matthew Arnold
  3. I think we ought to try it in three or four colors, if we are going to observe the day at all. – A Hazard of New Fortunes by William Dean Howells