Inactive shearer's double (4,6)
I believe the answer is:
dead ringer
'double' is the definition.
(I've seen this before)
'inactive shearer's' is the wordplay.
'inactive' becomes 'dead' (similar in meaning).
'shearer's' becomes 'ringer' (I am not sure about this - if you are sure you should believe this answer much more).
'dead'+'ringer'='DEAD-RINGER'
Can you help me to learn more?
(Other definitions for dead ringer that I've seen before include "Quasimodo at end of novel?" , "Lookalike" , "Likeness" , "Spitting image" , "One can do no more changes!" .)