Noun:
* Prewriting is the process of brainstorming and planning before writing.
Verb:
* To prewrite means to engage in the planning and brainstorming activities before writing.
Here are some examples:
Noun:
* "I spent an hour in prewriting before I started writing the essay."
* "The teacher emphasized the importance of prewriting in class."
Verb:
* "We prewrote our ideas on the whiteboard."
* "I like to prewrite using mind maps."
So, the part of speech depends on the context.