misuser

plural misusers

1. A person who misuses something.

   Wretched misusers of language.

   c. 1812, Samuel Taylor Coleridge, The Friend

   1 more example

   He said that lessons from the pilots would be carried forward into the plan to dock the benefits of drug misusers who failed to attend for job interviews.

   2009 February 28, Alan Travis, “Scheme to dock benefits of offenders defaulting on sentences is wound up”, in The Guardian

2. lawunlawful use of a right; use in excess of, or varying from, one's right