On the wagon (8)
I believe the answer is:
teetotal
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">on the wagon</span>' is the definition.<br/ ><span class="explanation-format__explanation">(on the wagon can mean abstaining from alcohol)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for teetotal that I've seen before include "Eschewing booze" , "Sober" , "Never drinking alcohol" , "Abjuring alcohol" , "Sworn off alcohol" .)