Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
unachievable is an adjective meaning "impossible to achieve". It carries one recorded sense.
impossible to achieve
“an unattainable goal”
Definitions, synonyms and semantic relations for unachievable come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.