Get a beating over nothing — not lashed (5)
I believe the answer is:
loose
'not lashed' is the definition.
'get a beating over nothing' is the wordplay.
'get a beating' becomes 'lose' (to suffer a bad defeat eg in sport).
'over' indicates putting letters inside.
'nothing' becomes 'o' (looks like zero - 0).
'lose' placed around 'o' is 'LOOSE'.
(Other definitions for loose that I've seen before include "Showing fast behaviour" , "Unrestricted" , "Unfettered" , "Not fitting tightly" , "easy with one's favours" .)