Overturning of lie doing away with large worry (3)
I believe the answer is:
eat
'worry' is the definition.
(something worrying may eat someone up)
'overturning of lie doing away with large' is the wordplay.
'overturning of' is a reversal indicator (I've seen 'overturning' mean this).
'lie' becomes 'tale' (as in telling tales).
'doing away with' is a deletion indicator.
'large' becomes 'L' (eg in clothes sizes).
'tale' with 'l' removed is 'tae'.
'tae' reversed gives 'EAT'.
(Other definitions for eat that I've seen before include "Consume (food)" , "Corrode" , "Break bread" , "Munch" , "Bit, chew and swallow" .)