Again flick up whip (6)
I believe the answer is:
pilfer
'whip' is the definition.
'again flick up' is the wordplay.
'again flick' becomes 'reflip' ('flip' can be a synonym for 'flick' so perhaps 'reflip' is OK for 'again flick').
'up' is a reversal indicator (in down clue: letters go upwards).
'reflip' in reverse letter order is 'PILFER'.
(Other definitions for pilfer that I've seen before include "twenty-two ball game" , "Lift -- nick" , "Steal (sl.)" , "Steal (little things)" , "appropriate" .)