Appealing to cut energy (4)
I believe the answer is:
cute
'appealing' is the definition.
(I've seen this before)
'cut energy' is the wordplay.
'energy' becomes 'e' (physics symbol as in E=mc2).
'cut'+'e'='CUTE'
'to' acts as a link.
(Other definitions for cute that I've seen before include "Smart" , "Attractive or ingenious" , "Fly" , "Endearingly pretty" , "Small and attractive - cunning" .)