Accountant turned up little cash — this may be grave (6)
I believe the answer is:
accent
'this may be grave' is the definition.
(grave accent is a type of accent mark)
'accountant turned up little cash' is the wordplay.
'accountant' becomes 'CA' (abbreviation for chartered accountant).
'turned up' says the letters should be written in reverse.
'little cash' becomes 'cent' (eg small amount of cash in US coinage).
'ca' back-to-front is 'ac'.
'ac'+'cent'='ACCENT'
(Other definitions for accent that I've seen before include "It could be acute" , "Here's, maybe, a grave" , "Distinctive manner of oral expression" , "intensity" , "Place stress on, say a syllable" .)