Increase in wage level accommodates union's core requirement (5)
I believe the answer is:
raise
'increase' is the definition.
(raise can mean to increase or put up)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for raise that I've seen before include "Lift, elevate" , "What a poker player might do" , "Haul up" , "Pick up" , "Aries (anag)" .)