Cheap item brings defeat to chief (4,6)
I believe the answer is:
loss leader
'cheap item' is the definition.
'loss leader' can be an answer for 'item' (thesaurus). I'm not sure about the 'cheap' bit.
'defeat to chief' is the wordplay.
'defeat' becomes 'loss' (I've seen this in other clues).
'to chief' becomes 'leader' (I've seen this before).
'loss'+'leader'='LOSS-LEADER'
'brings' acts as a link.
Can you help me to learn more?
(Other definitions for loss leader that I've seen before include "Product sold cheaply to attract buyers" , "bait for shoppers" , "Item sold cheaply to attract trade" , "Article sold at no profit in order to draw customers" , "Encouraging reduction" .)