Squander rupees, becoming more dejected (5)
I believe the answer is:
bluer
'more dejected' is the definition.
(blue can mean sad or dejected)
'squander rupees' is the wordplay.
'squander' becomes 'blue' (blue can mean to waste or squander).
'rupees' becomes 'r' (abbreviation for rupees).
'blue'+'r'='BLUER'
'becoming' acts as a link.
(Other definitions for bluer that I've seen before include "bawdier" , "less in the red?" , "More conservative" , "Wastrel" , "more despondent" .)