Brown more stupid to get rid of gold, ultimately (5)
I believe the answer is:
umber
'brown' is the definition.
(umber is a kind of brown)
'more stupid to get rid of gold ultimately' is the wordplay.
I cannot really see how this works, but
'more' could be 'm' and 'm' is found in the answer.
'get' could be 'be' ('get' can mean 'come to be') and 'be' is located in the answer.
The remaining letters 'ur' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for umber that I've seen before include "Usually dark brown mineral" , "Brownish pigment" , "Dark brown (pigment)" , "Earthy colour" , "Brown earthy mineral" .)