pertinacious
Concise Oxford English Dictionary © 2008 Oxford University Press:
pertinacious /ˌpəːtɪˈneɪʃəs/
▶adjective formal stubborn; persistent.
– derivatives
pertinaciously adverb,
pertinaciousness noun,
pertinacity noun.
pertinaciously adverb,
pertinaciousness noun,
pertinacity noun.
'pertinacious' also found in these Oxford entries:

