payback

noun

1. the period of time required to recoup a capital investment.
2. the return on an investment: a payback of 15 percent tax-free.
3. the act or fact of paying back; repayment.
4. something done in retaliation: a really vicious payback for years of being snubbed.

n.also pay-back, 1946, “net return on profits from an investment,” from pay (v.) + back (adj.). Meaning “revenge” is attested from 1957.