old-age pension vs retirement pension

old-age pension and retirement pension both are nouns.

Word	Noun	Adjective	Verb	Adverb
old-age pension	Yes	No	No	No
retirement pension	Yes	No	No	No

As nouns, old-age pension and retirement pension are synonyms defined as:

old-age pension and retirement pension: a monthly payment made to someone who is retired from work

Other synonyms of old-age pension include retirement benefit, retirement check, retirement fund, superannuation.

old-age pension (noun)	retirement pension (noun)
a monthly payment made to someone who is retired from work	a monthly payment made to someone who is retired from work