Measure productive sides lapsing in comeback (5)
I believe the answer is:
litre
'measure' is the definition.
(litre is a kind of measure)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for litre that I've seen before include "Approx 1 point 75 pints" , "One cubic decimetre" , "Unit of capacity in metric system" , "Amount of liquid" , "Metric liquid measure" .)