title_body: Term for the converse of "instrumental" We can make a noun for the instrument of an action, by taking the verb for the action and adding an instrumental marker.[1]
  
  For instance, in English, we can add "-er",[2] 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"?
  
  
  
  [1] 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.
  
  [2] This is also the agentive suffix in English, but I'm imagining a scenario where the agent and the instrument are clearly distinguished.
upvoted_answer: I think you're conflating a/o confusing a couple different things here.
  
  First, "cutter" is not "instrumental". (At least in English!) In English grammar, -er is (among zillions of other uses) the morpheme that indicates "agent noun"; so, cutter means "thing that cuts". It is the actual agent by which cutting happens.
  
  The Instrumental Case is a grammatical function that indicates the means by which the agent or subject of the verb does the action:
  
  
  I-subj cut-verb the.box-obj (with.a.box.cutter)-instr.
  
  
  If English had case endings like Latin, you could see the difference easily:
  
  
  Puer-NOM cistam-ACC cultello-ABL secavit-VERB
  
  
  Latin uses the ablative case to denote the instrumental case, due to ancient case syncretism of the old ablative, locative and instrumental cases.
  
  -ise / -ize, in English, is a grammatical morpheme that indicates the word is a denominal verb. This means that the verb in question is made from a noun. We already know that English weirds. It verbs nouns at the drop of a hat.
  
  
  I will hammer him if he attacks me with the knife.
  
  
  Your example, "I will hammerise him if he attacks me with a knife", doesn't actually make sense in context. This is because -ise doesn't mean "use something as an instrument", it means "turn something into something else".
  
  
  Immigrants ought to be Americanised through educational programmes.
  The machine pulverises large pieces of stone into gravel.
  
  
  
  
  I think your best bet, as far as "converse" of or "opposite" of the instrumental case, would be the
  
  noninstrumental case, which I just made up.  It does what the instrumental case does, only in the other direction. Essentially, the speaker denies the instrumentality of the named article.
  
  
  Puer-NOM cistam-ACC cultellei-NONINST secavit-VERB
  
  
  I considered "deinstrumental", but that's already a thing (a noun or verb made upon an instrumental form).