Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
off-guard is an adjective meaning "not prepared or vigilant". It carries one recorded sense.
not prepared or vigilant
“the blow caught him napping”
“caught in an off-guard moment”
“found him off his guard”
Definitions, synonyms and semantic relations for off-guard come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.