body armor vs suit of armour

body armor and suit of armour both are nouns.

Word	Noun	Adjective	Verb	Adverb
body armor	Yes	No	No	No
suit of armour	Yes	No	No	No

As nouns, body armor and suit of armour are synonyms defined as:

body armor and suit of armour: armor that protects the wearer's whole body

Other synonyms of body armor include body armour, cataphract, coat of mail, suit of armor.

body armor (noun)	suit of armour (noun)
armor that protects the wearer's whole body	armor that protects the wearer's whole body