He almost sailed back (5)
I believe the answer is:
elias
'he' is the definition.
'almost sailed back' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'back' is a reversal indicator.
'sailed' with its final letter taken off is 'saile'.
'saile' written backwards gives 'ELIAS'.
(Other definitions for elias that I've seen before include "Hebrew prophet" , "Fellow" .)