In favour of (3)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">in favour of</span>' is the definition.<br/ ><span class="explanation-format__explanation">(being for a particular cause)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for for that I've seen before include "In support of" , "On the side of" , "Approving" , "Pro" , "See 24" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">in favour of</span>' is the definition.<br/ ><span class="explanation-format__explanation">(being pro a particular cause)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for pro that I've seen before include "Expert (abbr)" , "For; non-amateur" , "In short, not an amateur" , "Competent person" , "Paid worker" .)