off your guard vs napping

off your guard and napping both are adjectives.

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

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

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

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