keep tabs on vs observe

keep tabs on and observe both are verbs.

Word	Noun	Adjective	Verb	Adverb
keep tabs on	No	No	Yes	No
observe	No	No	Yes	No

As verbs, observe is a hypernym of keep tabs on; that is, observe is a word with a broader meaning than keep tabs on:

Other hypernyms of keep tabs on include follow, keep an eye on, watch, watch over.

keep tabs on (verb)	observe (verb)
keep a record on or watch attentively	stick to correctly or closely
	make mention of
	watch attentively
	observe with care or pay close attention to
	discover or determine the existence, presence, or fact of by perception with the eyes
	follow with the eyes or the mind
	show respect towards
	behave as expected during of holidays or rites
	conform one's action or practice to