eld vs old age

eld and old age both are nouns.

Word	Noun	Adjective	Verb	Adverb
eld	Yes	No	No	No
old age	Yes	No	No	No

As nouns, eld and old age are synonyms defined as:

Other synonyms of eld include age, geezerhood, years.

eld (noun)	old age (noun)
a late time of life	a late time of life
a time of life (usually defined in years) at which some particular qualification or power arises