Indigent

Circa 1400, Middle French, from Latin indigentem, form of indigere ("to need"), from indu ("in, within") + egere ("be in need, want").

Online Etymology Dictionary

Online Etymology Dictionary|indigence

Only relation to antonym affluent is common Latinate suffix + -ent.

Full definition of indigent

1830, Journal of the House of Delegates of the Commonwealth of Virginia, Thomas Ritchie (1830), page 422:Many of the indigent children are so badly provided for by their parents, with both food and raiment, that they cannot attend school regularly; ...
1974, Guy Davenport, Tatlin!:I had since my introduction to the prince been sensitive to the fact that he must think an obviously indigent soldier of fortune will sooner or later open the subject of a subscription to the Greek Cause.
2011, Carla Ulbrich, How Can You Not Laugh at a Time Like This?: Reclaim Your Health With Humor, Creativity, and Grit, Tell Me Press (2011), ISBN 9780981645346, page 65:Because of this, when my second major health fiasco happened, I had no insurance, so I went to a teaching hospital where they took indigent patients.
2013, Larry J. Siegel & John L. Worral, Essentials of Criminal Justice, Wadsworth (2013), ISBN 9781111835569, page 162:In numerous Supreme Court decisions since Gideon v. Wainwright, the states have been required to provide counsel for indigent defendants at virtually all other stages of the criminal process, beginning with arrest and concluding with the defendant's release from the system.

(plural indigents)

1975, Robertson Davies, World of Wonders, Penguin Books (1976), ISBN 0140043896, page 161:I liked the streets best, so I walked and stared, and slept in a Salvation Army hostel for indigents. But I was no indigent; I was rich in feeling, and that was a luxury I had rarely known.
2009, Mara Vorhees, Moscow, Lonely Planet (2009), ISBN 9781740598248, page 29:The influx of indigents overwhelmed the city's meagre social services and affordable accommodation.
2011, Michael Parenti, Democracy for the Few, Wadsworth (2011), ISBN 9780495911265, page 78:Then in 2005 a Republican-led Congress passed a bill requiring millions of low-income people to pay higher co-payments and premiums under Medicaid. The result was that many more indigents had to forgo care.