What is another word for tenacious of?
Pronunciation: [tɛnˈe͡ɪʃəs ɒv] (IPA) 
Tenacity is an admirable quality, but sometimes one might need a change of phrase to express determination. Some synonyms for "tenacious of" include "persistent in," "fanatical about," "unwavering in," "obstinate in," "strong-willed in," "relentless in," "dogged about," and "firm in." Each of these synonyms conveys the idea of a person who is unshakeable in their pursuit of a goal. Whether it be professional, romantic, or personal, using these alternative phrases can allow one to add some variety to their language and express their unwavering dedication in a fresh and interesting manner.
