Fuss about a soldier’s leisurely movement (6)
I believe the answer is:
adagio
'leisurely movement' is the definition.
(I've seen this before)
'fuss about a soldier's' is the wordplay.
'fuss' becomes 'ado' (synonyms).
'about' indicates putting letters inside.
'soldier' becomes 'gi' (government issue or general issue).
'a'+'gi'='agi'
'ado' going around 'agi' is 'ADAGIO'.
(Other definitions for adagio that I've seen before include "In music, leisurely" , "In slow time (music)" , "Leisurely, musically speaking" , "Slowly and graceful, in music" , "' - - for Strings' (Barber)" .)