Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
nerve-wracking is an adjective meaning "extremely irritating to the nerves". It carries one recorded sense.
extremely irritating to the nerves
“nerve-racking noise”
“the stressful days before a war”
“a trying day at the office”
Definitions, synonyms and semantic relations for nerve-wracking come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.