Particularly large stick raised over boy's bottom (7)
I believe the answer is:
notably
'particularly' is the definition.
(I've seen this before)
'large stick raised over boy's bottom' is the wordplay.
'large' becomes 'L' (eg in clothes sizes).
'stick' becomes 'baton' (term for a stick or staff).
'raised' says the letters should be written backwards (going up in a down clue).
'over' says to put letters next to each other.
'bottom' suggests the final letters.
The last letter of 'boy' is 'y'.
'l'+'baton'='lbaton'
'lbaton' backwards is 'notabl'.
'notabl'+'y'='NOTABLY'
(Other definitions for notably that I've seen before include "in particular" , "Particularly" , "with remarkable results?" .)