Mid 17th century; earliest use found in Thomas Blount (1618–1679), antiquary and lexicographer. From classical Latin armifer bearing arms, warlike + -ous; compare -ferous.
Definition of armiferous in US English:
armiferous
adjectiveɑːˈmɪf(ə)rəs
rare
Bearing weapons or armour; warlike, bellicose.
Origin
Mid 17th century; earliest use found in Thomas Blount (1618–1679), antiquary and lexicographer. From classical Latin armifer bearing arms, warlike + -ous; compare -ferous.