Tenacious means holding on tightly and refusing to give up, even when things get difficult. A tenacious person keeps trying despite obstacles, setbacks, or discouragement.

Think of a dog with a rope toy, gripping it firmly in its teeth and refusing to let go no matter how much you pull. That physical grip captures what tenacity feels like mentally: a determined refusal to quit. A tenacious student working on a challenging math problem keeps trying different approaches until something clicks. A tenacious athlete practices the same skill over and over, knowing that improvement takes time and repetition.

You can be tenacious about pursuing a goal, defending an idea you believe in, or solving a problem that stumps everyone else. Scientists who make breakthroughs often show remarkable tenacity, working for years on questions that others have abandoned.

Tenacity (the noun form) describes this quality of persistent determination. While stubbornness means refusing to change your mind (which isn't always good), tenacity means refusing to give up on something worthwhile. When you show tenacity, you demonstrate that some goals matter enough to keep pursuing them, even when success seems distant.