Deer's back, lassoed by worker's chain (6)
I believe the answer is:
anklet
'chain' is the definition.
(thesaurus)
'deer's back lassoed by worker's' is the wordplay.
'deer' becomes 'elk' (elk is a kind of deer).
'back' says the letters should be written in reverse.
'lassoed by' is an insertion indicator.
'worker' becomes 'ant' (worker is a type of ant).
'elk' back-to-front is 'kle'.
'kle' placed inside 'ant' is 'ANKLET'.
(Other definitions for anklet that I've seen before include "Adornment on leg" , "footwear" , "Jewellery worn around the bottom of the leg" , "leg chain" , "Fetter" .)