Sailor returned to show an old card game (5)
I believe the answer is:
tarot
'card game' is the definition.
(I've seen this in another clue)
'sailor returned to' is the wordplay.
'sailor' becomes 'tar' (term for a sailor).
'returned' says the letters should be written in reverse.
'to' in reverse letter order is 'ot'.
'tar'+'ot'='TAROT'
'show an old' is the link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for tarot that I've seen before include "Arcana cards" , "Picture card" , "Set of cards used by fortune-tellers" , "Fortune teller's seventy eight card pack" , "Playing cards" .)