Soldiers welcoming European fighter's practicality (7)
I believe the answer is:
realism
'practicality' is the definition.
(I know that realism is a type of practicality)
'soldiers welcoming european fighter's' is the wordplay.
'soldiers' becomes 'rm' (Royal Marines).
'welcoming' indicates putting letters inside (in sense of 'inviting in').
'european' becomes 'E' (abbreviation e.g. EU).
'fighter's' becomes 'Ali's' (boxer Muhammad Ali).
'e'+'alis'='ealis'
'rm' going around 'ealis' is 'REALISM'.
(Other definitions for realism that I've seen before include "Seeing things as they are" , "True-to-life quality" , "The representation of things as they are" , "Actuality" , "True to life quality" .)