to seem to be; to appear; to behave as ~
Expresses that something or someone seems, appears, or behaves in a way characteristic of the noun it attaches to.
This pattern turns a noun into a verb meaning 'to have the appearance or manner of that noun'. It is often used with nouns that evoke a strong image or stereotype. For example, 大人びる means to act or look grown-up beyond one's years, while 子供びる (though less common) means to act childish. The form びた acts as a modifier, like a past participle, as in 大人びた顔 (a mature-looking face). The pattern is somewhat literary and is rarely used in casual conversation; you'll encounter it more in written narratives or formal descriptions.