Sticks up for attempt (4)
I believe the answer is:
stab
'for attempt' is the definition.
(to have a stab is to attempt something)
'sticks up' is the wordplay.
'sticks' becomes 'bats' (bat is a kind of stick).
'up' is a reversal indicator (in down clue: letters go upwards).
'bats' in reverse letter order is 'STAB'.
(Other definitions for stab that I've seen before include "It could be the death of you" , "Attempt (with dagger?)" , "Run through - essay" , "Pierce with pointed weapon" , "effort" .)