Stuffing knocked out of Lulu in break of service — retiring (9)
I believe the answer is:
reclusive
'retiring' is the definition.
(I've seen this before)
'stuffing knocked out of lulu in break of service' is the wordplay.
'stuffing knocked out of' suggests removing the centre (the letters which stuff into the word are removed).
'in' means one lot of letters goes inside another.
'break of' indicates anagramming the letters (I've seen 'broke' mean this).
'lulu' with its middle removed is 'lu'.
'service' anagrammed gives 'recsive'.
'lu' inserted within 'recsive' is 'RECLUSIVE'.
(Other definitions for reclusive that I've seen before include "retiring" , "Solitary" , "Hermit-like" .)