A few surround Frenchman in battle (5)
I believe the answer is:
somme
'battle' is the definition.
(Battle of the Somme in WW1)
'a few surround frenchman' is the wordplay.
'a few' becomes 'some' (both can mean a small amount of something).
'surround' indicates putting letters inside.
'frenchman' becomes 'm' (abbreviation for Monsieur - like 'Mr').
'some' enclosing 'm' is 'SOMME'.
'in' acts as a link.
(Other definitions for somme that I've seen before include "First World War battlefield" , "European river" , "bloody fight" , "French river known from World War 1" , "French river, scene of 1916 battles" .)