observe

/əb-ˈzərv/

Middle English observen "to follow, conform to, practice, celebrate," borrowed from Anglo-French & Latin; Anglo-French observer "to comply with, uphold" (also continental Old French), borrowed from Latin observāre "to give attention to, watch carefully, abide by, adhere to, celebrate," from ob- "toward, facing, against" + servāre "to watch over, guard, keep, observe (a law, custom)"

verb

  1. to conform one's action or practice to (something, such as a law, rite, or condition) : comply, with

  2. to inspect or take note of as an augury, omen, or presage

  3. to celebrate or solemnize (something, such as a ceremony or festival) in a customary or accepted way

failed to observe the law and as a consequence had to pay a fine

keep observe celebrate commemorate mean to notice or honor a day, occasion, or deed. keep stresses the idea of not neglecting or violating. observe suggests marking the occasion by ceremonious performance.

idiom

  1. to behave with politeness

We have never really liked each other, but we observe the social amenities whenever we meet.