Base of bed quite clean but hollow (4)
I believe the answer is:
dent
'hollow' is the definition.
(both can mean an impression or indentation)
'base of bed quite clean but' is the wordplay.
'base of' suggests the final letters.
The last letters of 'bed quite clean but' are 'DENT'.
(Other definitions for dent that I've seen before include "Hollow from impact" , "Injury to pride" , "Tend to small indentation" , "A cavity" , "Arthur, described by Douglas" .)