tenacious
te|na|cious /tɪn'eɪʃəs/
1 [ADJ]
If you are tenacious, you are very determined and do not give up easily.
He is regarded at the BBC as a tenacious and persistent interviewer.
● tenaciously [ADV] usu ADV after v
In spite of his illness, he clung tenaciously to his job.
2 [ADJ]
If you describe something such as an idea or belief as tenacious, you mean that it has a strong influence on people and is difficult to change or remove.
...a remarkably tenacious belief that was to dominate future theories of military strategy.
= deep-seated
1 [ADJ]
If you are tenacious, you are very determined and do not give up easily.
He is regarded at the BBC as a tenacious and persistent interviewer.
● tenaciously [ADV] usu ADV after v
In spite of his illness, he clung tenaciously to his job.
2 [ADJ]
If you describe something such as an idea or belief as tenacious, you mean that it has a strong influence on people and is difficult to change or remove.
...a remarkably tenacious belief that was to dominate future theories of military strategy.
= deep-seated