No uncertain weight is displayed there (5)
I believe the answer is:
ounce
'no uncertain weight is displayed there' is the definition.
I can't tell whether this defines the answer.
'no uncertain weight is displayed' is the wordplay.
'is displayed' says the answer is hidden in the clue (the answer is displayed within the clue).
'OUNCE' is hidden in the letters of 'no uncertain weight'.
Can you help me to learn more?
(Other definitions for ounce that I've seen before include "Small quantity - weight" , "A light weight - feline" , "One cat" , "Wildcat" , "weight? Surely not" .)