installment rate vs repayment rate

installment rate and repayment rate both are nouns.

Word	Noun	Adjective	Verb	Adverb
installment rate	Yes	No	No	No
repayment rate	Yes	No	No	No

As nouns, installment rate and repayment rate are synonyms defined as:

installment rate and repayment rate: the amount of money paid out per unit time

Other synonyms of installment rate include payment rate, rate of payment.

installment rate (noun)	repayment rate (noun)
the amount of money paid out per unit time	the amount of money paid out per unit time