Staff charge is steep (8)
I believe the answer is:
macerate
'is steep' is the definition.
(thesaurus)
'staff charge' is the wordplay.
'staff' becomes 'mace' (mace is a kind of staff).
'charge' becomes 'rate' (rate is a kind of charge**).
'mace'+'rate'='MACERATE'
(Other definitions for macerate that I've seen before include "Soften food by soaking" , "Cream tea (anag) -- soften by steeping in liquid" , "Soak" , "Steep in liquid like cream tea" .)