Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
causeless is an adjective meaning "having no justifying cause or reason". It carries 2 recorded senses.
having no justifying cause or reason
“a senseless, causeless murder”
“a causeless war that never had an aim”
“an apparently arbitrary and reasonless change”
having no cause or apparent cause
“a causeless miracle”
“fortuitous encounters--strange accidents of fortune”
“we cannot regard artistic invention as...uncaused and unrelated to the times”
Definitions, synonyms and semantic relations for causeless come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.