What is the meaning of Fier?

Archaic form of fire.

fern

proud

for

four

fair

Alternative form of figer

Alternative form of fyr

to trust (someone, something)

Alternative form of fer (cruel; fierce)

iron

proud

remarkable (in this sense always used before the noun it qualifies)

to trust someone (à), to rely on someone (à)

iron

tool made of iron

iron

far, distant

Source: wiktionary.org