I am cutting weight in half to become member (4)
I believe the answer is:
limb
'member' is the definition.
(limb is a kind of member)
'i am cutting weight in' is the wordplay.
'i am' becomes 'im'.
'cutting' means to remove the last letter.
'weight' becomes 'lbs'.
'in' indicates putting letters inside.
'lbs' with its last letter taken away is 'lb'.
'im' put into 'lb' is 'LIMB'.
'half to become' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for limb that I've seen before include "Eg wing" , "Bough" , "Branch - arm - leg" , "Human's extension" , "Large tree branch" .)