Absurd! Stupid to refuse shilling (5)
I believe the answer is:
inane
'absurd' is the definition.
(I've seen this before)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for inane that I've seen before include "Vapid, fatuous" , "Empty-headed" , "Daft" , "Puerile" , "Silly, fatuous" .)