Youthful means having the energy, appearance, or spirit of someone young. A youthful person might be actually young, or they might be older but still full of enthusiasm and vitality. Your grandmother who loves trying new hobbies, stays curious about the world, and laughs easily has a youthful spirit, even if her hair has turned gray.

The word describes qualities beyond chronological age. A youthful attitude means approaching life with optimism and wonder, like when you're excited to explore a new place or learn a new skill. Someone with youthful energy might bounce out of bed ready for adventure, while youthful looks might mean smooth skin and bright eyes.

You'll also see youthful describe mistakes or choices that come from inexperience. A youthful error is the kind of mistake someone makes because they haven't learned better yet, like thinking you can stay up all night and still feel great the next day.

The related word youth refers to the time of being young, or to young people as a group. When adults talk about “the youth of today,” they mean your generation. Your youth is this special time in your life right now, full of growth and possibility.