Infantryman (7)
(Other definitions for trooper that I've seen before include "Cavalryman" , "Proverbially swearing soldier" , "Private soldier" , "Soldier, proverbial swearer" , "He swears" .)
'infantryman' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for soldier that I've seen before include "Member of a fighting force" , "Enlisted man or woman" , "One of man's 22 20 [SEVEN AGES]" , "Army man" , "piece of toast" .)
'infantryman' is the definition.
(I know that grenadier is a type of infantryman)
This is the entire clue.
(Other definitions for grenadier that I've seen before include "guard" , "Infantryman - in red gear (anag)" , "Soldier - in red gear (anag)" , "A household infantryman" , "African flier" .)
'infantryman' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for foot soldier that I've seen before include "Infantryman" , "Valuable but lowly worker" .)