Rinse out warning device (5)
I believe the answer is:
siren
'warning device' is the definition.
(I've seen this in another clue)
'rinse out' is the wordplay.
'out' is an anagram indicator (out can mean wrong or inaccurate).
'rinse' with letters rearranged gives 'SIREN'.
(Other definitions for siren that I've seen before include "Hooter - dangerous woman?" , "Rinse (anag) - sea nymph" , "Temptress - warning device" , "Seductress" , "Loud whistle or kind of witch" .)