Matelot losing friend finds destiny (3)
I believe the answer is:
lot
'destiny' is the definition.
(I know that destiny can be written as lot)
'matelot losing friend' is the wordplay.
'losing' indicates named letters should be taken away.
'friend' becomes 'mate' (mate is a kind of friend).
'matelot' with 'mate' taken away is 'LOT'.
'finds' is the link.
(Other definitions for lot that I've seen before include "A person's luck" , "is to be knocked down" , "Parcel - collection" , "Portion in life" , "Nephew of Abraham - batch" .)