Tenacious – Keeping a firm hold; not giving up easily

Ten acres! (tenacious) I won't give up until I have ten acres.

Examples of tenacious used in a sentence

Williams is a tenacious opponent, she never gives in.

He became famous for his tenacious nerves, physical courage, exceptional organization and planning skills.

Despite its tenacious defence, the team lost in the first round each time it made the playoffs.