A large amount (6)
(Other definitions for oodles that I've seen before include "'Lashings, heaps (6)'" , "A great many" , "wealth" , "Very great amount (colloq.)" , "Loosed among lots" .)
(Other definitions for stacks that I've seen before include "Orderly heaps as of hay" , "A lot (of hay?)" , "Large tall chimneys" , "Tons" , "bags?" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">a large amount</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 plethora that I've seen before include "Unnecessarily large quantity" , "Profusion" , "Glut, over-abundance" , "More than enough" , "Embarrassment" .)