Is questioning a verb or noun?

"Questioning" can be both a verb and a noun, depending on its function in a sentence.

Verb:

* "Questioning" means to ask a question or to express doubt.

* Example: "She is questioning the validity of the study."

Noun:

* "Questioning" can also be a noun that refers to the act of asking questions.

* Example: "The questioning of witnesses lasted for hours."

Therefore, you need to consider the context to determine which part of speech "questioning" is in a specific sentence.