Lower in value (6)
I believe the answer is:
debase
'lower in value' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for debase that I've seen before include "Lower in quality or value, corrupt" , "Depreciate or humiliate" , "Lower in quality, reduce the value of" , "Lower, degrade" , "Humble" .)