Unreasonably short utensil (3)
I believe the answer is:
too
'unreasonably' is the definition.
(thesaurus)
'short utensil' is the wordplay.
'short' means to remove the last letter.
'utensil' becomes 'tool' (I've seen this before).
'tool' with its final letter taken off is 'TOO'.
(Other definitions for too that I've seen before include "As well; in addition" , "Moreover, in addition" , "Unduly" , "Excessively" , "Furthermore" .)