We can make a noun for the instrument of an action, by taking the verb for the action and adding an instrumental marker.
For instance, in English, we can add "-er", like so:
I cut the box with a box-cutter.
Conversely, we can make a verb for an action, by taking the noun for the instrument and adding... what could you call it?
In English, we don't necessarily have an affix, since we can just verbalise the noun, like so:
I will knife you with my knife.
...but we might use "-ise" this way, at least jocularly:
I will hammerise him if he comes at me with that knife.
So is there a term for such a marker, indicating the use of an instrument? "Usive"? "Usual"?
 I was going to call this "instrumentive", on the pattern of "agentive" and "patientive", but the word doesn't appear in any dictionary I checked. It is used in some books on linguistics, though, per Google Books.
 This is also the agentive suffix in English, but I'm imagining a scenario where the agent and the instrument are clearly distinguished.