Verb (5-dan, す, transitive)
1. to finish; to get it over with; to conclude
だったら、早く済ましたらどうだ？If that's the case, why don't you just get it over with quickly?
2. to settle; to pay back
借金を全部済ました。I paid off all my debts.
3. to get along (without something); to make do with (without)
often with で
今夜はシャワーだけで済ます。I'll just take a shower tonight.