Seaman has a vice, these endless alcoholic spirits (9)

'alcoholic spirits' is the definition.
Although both the answer and definition are plural nouns, I can't see how one could define the other.

'seaman has a vice these endless' is the wordplay.
'seaman' becomes 'ab' (short for able seaman).
'has' is a charade indicator (letters next to each other).
'a vice' becomes 'sin'.
'endless' means to remove the last letter.
'these' with its final letter removed is 'thes'.
'ab'+'sin'+'thes'='ABSINTHES'

Can you help me to learn more?