Doctor's client (7)
I believe the answer is:
patient
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">doctor's client</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for patient that I've seen before include "One receives medical care" , "Prepared to wait" , "Doctor's 'customer'" , "sick person" , "Sufferer" .)