Abandoned taking action about disturbed rest (8)
I believe the answer is:
deserted
'abandoned' is the definition.
('desert' can be a synonym of 'abandon')
'action about disturbed rest' is the wordplay.
'action' becomes 'deed' (deed is a kind of action).
'about' means one lot of letters goes inside another.
'disturbed' indicates an anagram.
'rest' with letters rearranged gives 'sert'.
'deed' enclosing 'sert' is 'DESERTED'.
'taking' acts as a link.
(Other definitions for deserted that I've seen before include "Left the armed forces without permission" , "Abandoned or defected" , "uncultivated" , "Abandoned, forsook" , "Ran away from army" .)