Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
high-sounding is an adjective meaning "pretentious (especially with regard to language or ideals)". It carries one recorded sense.
pretentious (especially with regard to language or ideals)
“high-flown talk of preserving the moral tone of the school”
“a high-sounding dissertation on the means to attain social revolution”
colloquialism
Definitions, synonyms and semantic relations for high-sounding come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.