Propagate (5)
I believe the answer is:
breed
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">propagate</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 breed that I've seen before include "Generate" , "Rear; variety" , "Special variety of domesticated animal" , "Special lineage" , "Lead to (success); kind" .)