Financial supporter (6)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">financial supporter</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for backer that I've seen before include "Angel" , "A supporter or a betting man" , "Financial supporter" , "Person supporting another financially" , "Sponsor" .)
(Other definitions for benefactor that I've seen before include "Person giving to a good cause" , "charity supporter?" , "One provides bread" , "Patronising sort" , "Patron, sponsor" .)
(Other definitions for sponsor that I've seen before include "One offering support" , "Patron; promote" , "Supporter or champion" , "One who pays costs for event" , "Promoter; funder" .)