Burros (5)
I believe the answer is:
asses
'burros' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for asses that I've seen before include "More than one fool" , "not the most sensible types" , "Small, sure-footed animals" , "Pompous fools" , "Animals of horse family" .)