Dives off with European plan (6)
I believe the answer is:
devise
'plan' is the definition.
('devise' can be a synonym of 'plan')
'dives off with european' is the wordplay.
'off with' indicates an anagram.
'european' becomes 'e' (abbreviation e.g. EU).
'dives' with its letters anagrammed with 'e' makes 'DEVISE'.
(Other definitions for devise that I've seen before include "Plan invent" , "Come up with, a plan perhaps" , "Make (a plan)" , "Invent in sieved fashion" , "Create, work out" .)