Join, as a club
I believe the answer is:
enter
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">join as a club</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 enter that I've seen before include "Go in and put in the ledger" , "Come in - penetrate - record" , "Introduce" , "Infiltrate" , "Register (as a competitor)" .)