Definitions for off-guard
napping, off-guard(a), off guard(p), off one's guard(p), off his guard, off her guard, off your guard(adj)
not prepared or vigilant
"the blow caught him napping"; "caught in an off-guard moment"; "found him off his guard"
Kernerman English Learner's Dictionary
not prepared to deal with sth
Home owners were caught off-guard by the severe flooding.