Easy copper, retiring (5)
I believe the answer is:
cushy
'easy' is the definition.
(similar in meaning)
'copper retiring' is the wordplay.
'copper' becomes 'cu' (chemical symbol).
'retiring' becomes 'shy' (I've seen this in other clues).
'cu'+'shy'='CUSHY'
(Other definitions for cushy that I've seen before include "(Of situation) secure, easy (colloq.)" , "Jammy" , "Not demanding" , "Simple" , "Easy, soft (colloq.)" .)