When you engage a lawyer or an estate agent, for example, you instruct them. What is the most appropriate word to use when you decide you've had enough and want to get rid of them? There are several good contenders but 'dis-instruct' would seem most appropriate - and yet I'm unable to find this word in any of the common reference dictionaries. Is it a legitimate word?
Google Ngram yielded the following, but only for 'dis - instruct'. All other possible constructions of this word flatlined.
Other possible constructions are uninstruct (although as back-formation of uninstructed there is potential for misinterpretation) and de-instruct.