Beat learner driver involved in crash (5)
I believe the answer is:
flail
'beat' is the definition.
(flailing is a kind of beating)
'learner driver involved in crash' is the wordplay.
'learner driver' becomes 'l' (I've seen this in other clues).
'involved in' indicates putting letters inside.
'crash' becomes 'fail'.
'l' going into 'fail' is 'FLAIL'.
(Other definitions for flail that I've seen before include "Thresh about" , "thrash around" , "Old tool for threshing grain" , "Thresher; wave helplessly about" , "Weapon; swing wildly" .)