Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
pertinaciously is an adverb meaning "in a dogged and pertinacious manner". It carries one recorded sense.
in a dogged and pertinacious manner
“he struggled pertinaciously for the new resolution”
Definitions, synonyms and semantic relations for pertinaciously come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.