what's the name of this kind of linguistical phenomenon ?

A word has a meaning as adj., meanwhile the same word also has a another meaning as verb.

Or, a word has a meaning as verb., meanwhile this word also has a meaning of noun.

In other words, one word could express different meanings, while acting as different grammar element.

How to describe this phenomenon professionally ?

Hi! I believe this is called a "homophone." You could also describe it as one word that may be used for multiple parts of speech.

Amy