A naval reject? (8)
I believe the answer is:
castaway
'reject?' is the definition.
(thesaurus)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for castaway that I've seen before include "Tom Hanks movie" , "Rejected person" , "worthless" , "just one left on the Strand?" , "Shipwreck survivor" .)