napping vs off one's guard

napping and off one's guard both are adjectives.

Word	Noun	Adjective	Verb	Adverb
napping	No	Yes	No	No
off one's guard	No	Yes	No	No

As adjectives, napping and off one's guard are synonyms defined as:

Other synonyms of napping include off-guard, off guard, off her guard, off his guard, off your guard.

napping (adjective)	off one's guard (adjective)
not prepared or vigilant	not prepared or vigilant