Large flower -- it's enticing (4)
I believe the answer is:
lure
'it's enticing' is the definition.
(a lure entices someone)
'large flower' is the wordplay.
'large' becomes 'L' (eg in clothes sizes).
'flower' becomes 'ure' (river in Yorkshire).
'l'+'ure'='LURE'
(Other definitions for lure that I've seen before include "draw" , "Attract with bait" , "'Entice, tempt (4)'" , "Tempt with bait" , "Enticement" .)