off guard vs napping

off guard and napping both are adjectives.

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

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

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

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