Cook some lunch effectively (4)
I believe the answer is:
chef
'cook' is the definition.
(both can mean someone who cooks)
'some lunch effectively' is the wordplay.
'some' says the answer is hidden in the clue (some parts of the word are used).
'CHEF' can be found hidden inside 'lunch effectively'.
(Other definitions for chef that I've seen before include "French master" , "Originator of courses" , "member of kitchen staff" , "one in the restaurant" , "responsible for courses" .)