Expedition to the French city goes round river (8)
I believe the answer is:
alacrity
'expedition' is the definition.
(I've seen this before)
'to the french city goes round river' is the wordplay.
'to the french' becomes 'a la' ('to the' in French).
'goes round' means one lot of letters goes inside another.
'river' becomes 'r' (abbreviation for river).
'city' enclosing 'r' is 'crity'.
'ala'+'crity'='ALACRITY'
(Other definitions for alacrity that I've seen before include "Lively enthusiasm" , "'Briskness, promptness (8)'" , "Lively eagerness" , "prompt response" , "Prompt readiness and briskness" .)