Poles stopping work making organ (6)
I believe the answer is:
tonsil
'organ' is the definition.
(I've seen this before)
'poles stopping work' is the wordplay.
'poles' becomes 'ns' (North and South poles).
'stopping' indicates putting letters inside (stopping can mean blocking a gap).
'work' becomes 'toil' (toiling is a kind of working).
'ns' going into 'toil' is 'TONSIL'.
'making' acts as a link.
(Other definitions for tonsil that I've seen before include "Throat gland" , "One often removed" , "One of two at the back of the mouth" , "No slit at the base of the tongue" , "One of two pieces of tissue on the pharynx" .)