Ham's acknowledgment (5)
I believe the answer is:
roger
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">ham's acknowledgment</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for roger that I've seen before include "Chap" , "Jolly man" , "Radio confirmation" , "man, > I understand" , "Radio acknowledgment" .)