The word “Tenacious” means –

Answer - Firm and persistent.

• Tenacious:
English meaning: holding tightly onto something, or keeping an opinion in a determined way.
Bangla meaning: শক্ত করে আঁকড়ে রাখে এমন; নাছোড়বান্দা; ধৈর্যশীল।

Example:
- The baby took my finger in its tenacious little fist.
- There has been tenacious local opposition to the new airport.

Source: Cambridge Dictionary.