Build up a nest egg
I believe the answer is:
save
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">build up a nest egg</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for save that I've seen before include "Rescue for a rainy day?" , "Rescue or salt away" , "Spend less" , "Put by in vase" , "Hang on to" .)