fusilier UK /ˌfjuːzɪˈlɪəː/US /ˌfju.zɪˈlɪɚ/ noun3 •An infantryman armed with a form of flintlock musket. •(UK) A soldier in any of several regiments that once fought with such weapons. •A fish in family Caesionidae, related to snappers. formsfusiliers