Big ship linked with Spain's generosity (8)
I believe the answer is:
largesse
'generosity' is the definition.
(I know that largesse is a type of liberality)
'big ship linked with spain's' is the wordplay.
'big' becomes 'large' (synonyms).
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'linked with' is a charade indicator (letters next to each other).
'spain' becomes 'e' (abbreviation for Espana).
'large'+'ss'+'e'='LARGESSE'
(Other definitions for largesse that I've seen before include "Generous offering" , "Liberal gift" , "Generous giving" , "Generous disposal of gifts" , "Bounty, gift" .)