Having injected limb, chap gets bit of a habit (7)
I believe the answer is:
garment
'bit of a habit' is the definition.
'garment' can be an answer for 'habit' (thesaurus). I'm unsure of the 'bit of a' bit.
'having injected limb chap' is the wordplay.
'having injected' means one lot of letters goes inside another.
'limb' becomes 'arm' (arm is a kind of limb).
'chap' becomes 'gent' (both can mean a man).
'arm' inserted into 'gent' is 'GARMENT'.
'gets' acts as a link.
Can you help me to learn more?
(Other definitions for garment that I've seen before include "Vestment" , "Maybe a jacket" , "Something put on" , "Grant me (anag.)" , "Singular outfit" .)