Falling over everything (3)
I believe the answer is:
all
'everything' is the definition.
(all things)
'falling over' is the wordplay.
'over' indicates the answer is hidden within the clue (the clue contains or goes 'over' the answer).
'ALL' is hidden within 'falling'.
(Other definitions for all that I've seen before include "that's as many as there are" , "'Bless 'em - - ' (song)" , "in toto" , "Fully clad ..." , "Completely, everything" .)