Pithy joke about European passenger ship (3-5)
I believe the answer is:
one-liner
'pithy joke' is the definition.
(a one-line joke)
'about european passenger ship' is the wordplay.
'about' becomes 'on' (as in a book 'on' a certain topic).
'european' becomes 'E' (abbreviation e.g. EU).
'passenger ship' becomes 'liner' (eg a cruise liner).
'on'+'e'+'liner'='ONE-LINER'
(Other definitions for one-liner that I've seen before include "Terse joke" , "Witty remark in single short sentence" , "Quick gag" , "Quick joke?" , "Witty remark consisting of a short sentence" .)