A dhow ultimately remains flooded (5)
I believe the answer is:
awash
'flooded' is the definition.
(synonyms)
'a dhow ultimately remains' is the wordplay.
'ultimately' suggests the final letters.
'remains' becomes 'ash' (remains of a fire).
The last letter of 'dhow' is 'w'.
'a'+'w'+'ash'='AWASH'
(Other definitions for awash that I've seen before include "Flood" , "Crawling" , "Partly under water" , "Level with the water surface" , "Deluged" .)