Emotion makes Heather undercharge (7)
I believe the answer is:
feeling
'emotion' is the definition.
(I've seen this before)
'heather undercharge' is the wordplay.
I cannot quite see how this works, but
'heather' could be 'ling' (synonyms) and 'ling' is located in the answer.
The remaining letters 'fee' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'makes' is the link.
Can you help me to learn more?
(Other definitions for feeling that I've seen before include "Sympathy" , "Sense, emotion" , "Emotion; opinion" , "Sensation" .)