Insecticide (5-3)
There are a few possibilities for this:
sheep-dip
(Other definitions for sheep-dip that I've seen before include "Pesticide bath for proverbially silly animals" , "Fleece cleaner" , "'Pesticide mixture for ovines (5,3)'" , "Fleece disinfectant" , "Farm animal's bath" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">insecticide</span>' is the definition.<br/ ><span class="explanation-format__explanation">(pyrethrum is a kind of insecticide)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Another definition for pyrethrum that I've seen is " flower".)
(Other definitions for pyrethrin that I've seen before include "Extract from aromatic flowers" , "Compound" .)