Meaning

adjective sufficiently fat so as to have a pleasing fullness of figure

originRecorded since 1611, from chub (“short, thick fish species used as bait"; used metaphorically since 1558 for "lazy person”), an assibilated form of cub (“a lump, heap, mass”) and cob, from Middle English *cubbe (found only in derivative cubbel (“a block to which an animal is tethered”)), from Old Norse kubbr, kumbr (“block, stump, log”) and/or Old Norse kumben (“stumpy”), equivalent to chub + -y.…

Etymology from Wiktionary, CC BY-SA 3.0