Item at auction, American flower (5)
I believe the answer is:
lotus
'flower' is the definition.
(I've seen this before)
'item at auction american' is the wordplay.
'item at auction' becomes 'lot' (I've seen this before).
'american' becomes 'us'.
'lot'+'us'='LOTUS'
(Other definitions for lotus that I've seen before include "Water lily - fruit inducing forgetfulness" , "reason for indolence" , "Aquatic plant" , "Car manufacturer - plant" , "Sacred flower" .)