Shylock's beginning with his job being meagre (7)
I believe the answer is:
slender
'meagre' is the definition.
(I've seen this before)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for slender that I've seen before include "Thin and graceful" , "Lean" , "Slim and supple" , "Thin or narrow" , "Slight in form" .)