Mean to get upset about the copper's insight (6)
I believe the answer is:
acumen
'insight' is the definition.
(I've seen this before)
'mean to get upset about the copper's' is the wordplay.
'to get upset' indicates an anagram (I've seen 'getting upset' mean this).
'about' indicates putting letters inside.
'the copper' becomes 'Cu' (chemical symbol).
'mean' anagrammed gives 'amen'.
'amen' going around 'cu' is 'ACUMEN'.
(Other definitions for acumen that I've seen before include "Quick intelligence" , "perspicacity" , "'Shrewdness, astuteness (6)'" , "ingenuity" , "'Keenness, depth of perception (6)'" .)