Married Frenchman's one European lacking excitement (7)
I believe the answer is:
mundane
'lacking excitement' is the definition.
(I've seen this before)
'married frenchman's one european' is the wordplay.
'married' becomes 'm'.
'frenchman's one' becomes 'un' (one in French).
'european' becomes 'dane' (Dane is an example).
'm'+'un'+'dane'='MUNDANE'
(Other definitions for mundane that I've seen before include "Lacking excitement; worldly" , "Earthly; unexciting" , "Unexciting; of this world" , "Everyday, humdrum" , "Ordinary, of this world" .)