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-the-wall is an adjective meaning "conspicuously or grossly unconventional or unusual". It carries one recorded sense.
conspicuously or grossly unconventional or unusual
“restaurants of bizarre design--one like a hat, another like a rabbit”
“famed for his eccentric spelling”
“a freakish combination of styles”
“his off-the-wall antics”
“the outlandish clothes of teenagers”
“outre and affected stage antics”
Definitions, synonyms and semantic relations for off-the-wall come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.