Something you require when heartlessly nettled (4)
I believe the answer is:
need
'something you require' is the definition.
I can't tell whether this defines the answer.
'heartlessly nettled' is the wordplay.
'heartlessly' means to remove the middle letters.
'nettled' with its centre taken out is 'NEED'.
'when' acts as a link.
Can you help me to learn more?
(Other definitions for need that I've seen before include "state requiring relief" , "Rely on" , "Lack - demand" , "What's lacking" , "Require; want" .)