To espouse means to adopt and actively support a belief, cause, or way of life. When someone espouses an idea, they don't just quietly agree with it: they speak up for it, defend it, and try to convince others of its value.

A scientist might espouse a new theory about how planets form, presenting evidence and arguing for its validity at conferences. A teacher might espouse the importance of reading aloud to young children, explaining to parents why it matters and encouraging them to do it at home. When a political leader espouses certain principles, those ideas become closely associated with them.

The word carries a sense of public commitment. You might privately believe something, but when you espouse it, you're willing to stand behind it openly. A coach who espouses teamwork doesn't just mention it once: she builds practices around it, celebrates it when she sees it, and makes it central to how the team operates.