Sailor backed proposal to cut energy and ran off (9)
I believe the answer is:
absconded
'ran off' is the definition.
('abscond' can be a synonym of 'run off')
'sailor backed proposal to cut energy' is the wordplay.
'sailor' becomes 'ab' (abbreviation for able seaman).
'backed proposal' becomes 'seconded' (as in seconding a proposal or motion).
'to cut' is a deletion indicator.
'energy' becomes 'e' (physics symbol as in E=mc2).
'seconded' with 'e' taken out is 'sconded'.
'ab'+'sconded'='ABSCONDED'
'and' acts as a link.
(Other definitions for absconded that I've seen before include "Escaped" , "Ran away to avoid legal process" , "took French leave" , "Bolted, made off" , "Left to avoid arrest" .)