Sorceress a non-starter in desire (4)
I believe the answer is:
itch
'desire' is the definition.
(I know that itch is a type of desire)
'sorceress a non-starter' is the wordplay.
'sorceress' becomes 'witch' (synonyms).
'a non-starter' means to remove the first letter (the letter which starts the word is ignored).
'witch' with its initial letter taken away is 'ITCH'.
'in' is the link.
(Other definitions for itch that I've seen before include "Rash reaction?" , "A strong restless desire" , "It must be scratched" , "It needs to be scratched" , "Skin irritation" .)