observant vs law-abiding

observant and law-abiding both are adjectives.

Word	Noun	Adjective	Verb	Adverb
observant	No	Yes	No	No
law-abiding	No	Yes	No	No

As adjectives, observant and law-abiding are synonyms defined as:

observant and law-abiding: (of individuals) adhering strictly to laws and rules and customs

observant (adjective)	law-abiding (adjective)
paying close attention especially to details	(of individuals) adhering strictly to laws and rules and customs
(of individuals) adhering strictly to laws and rules and customs
quick to notice; showing quick and keen perception