elbow grease (8)
'elbow grease' is the definition.
(I know that elbow grease can be written as effort)
This is all the clue.
(Other definitions for effort that I've seen before include "Vigorous attempt" , "Strenuous exertion" , "'Endeavour, exertion (6)'" , "For eft (anag.)" , "Hard mental or physical work" .)
'elbow grease' is the definition.
(I know that elbow grease can be written as exertion)
This is the entire clue.
(Other definitions for exertion that I've seen before include "labour" , "Tire oxen with heavy effort" , "Physical or mental effort" , "Use of physical energy" , "Great effort" .)