Mission could be fashionable without some of the French (5)
I believe the answer is:
alamo
'mission' is the definition.
(famous mission and siege from the Texas revolution)
'fashionable without some of the french' is the wordplay.
'fashionable' becomes 'a la mode' (a la mode can mean trendy or fashionable).
'without' is a deletion indicator.
'some of the french' becomes 'de' ('of the' in French).
'alamode' with 'de' taken away is 'ALAMO'.
'could be' is the link.
(Other definitions for alamo that I've seen before include "The --, Texan mission besieged in 1836" , "The red planet" , "Texas fort, scene of famous siege by Mexican army" , "Mission building in Texas, site of famous siege by Mexico" , "Famous Texan mission" .)