Buttonhole (6)
I believe the answer is:
accost
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">buttonhole</span>' is the definition.<br/ ><span class="explanation-format__explanation">(both can mean to detain in conversation)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for accost that I've seen before include "Approach boldly or aggressively" , "Approach boldly and speak to" , "Approach and address (someone) aggressively" , "Buttonhole" , "Tackle" .)