napping vs off guard

napping and off guard both are adjectives.

Word	Noun	Adjective	Verb	Adverb
napping	No	Yes	No	No
off guard	No	Yes	No	No

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

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

napping (adjective)	off guard (adjective)
not prepared or vigilant	not prepared or vigilant