Footballing group crushing my plants (5)
I believe the answer is:
flora
'plants' is the definition.
(I've seen this before)
'footballing group crushing my' is the wordplay.
'footballing group' becomes 'fa' (Football Association).
'crushing' means one lot of letters goes inside another.
'my' becomes 'lor' (exclamation of surprise).
'fa' placed around 'lor' is 'FLORA'.
(Other definitions for flora that I've seen before include "growing flowers" , "__ MacDonald, heroine of the 1745 Jacobite rising" , "Plants of a region or age" , "list of plant life" , "Various plants" .)