Baggy means much too loose, hanging off the body. A jumper with no shape left in it.
Clothes are what go baggy: baggy trousers, a baggy cardigan, jeans gone baggy at the knee. It can be a fault or a fashion depending entirely on the decade. The word comes from bag, and the image is exact, since a baggy garment hangs the way an empty bag does. It also describes skin under the eyes, and by extension a piece of writing that is loose and needs tightening.
1adjectivebaggyLoose and hanging away from the body.
“He wore a baggy old jumper over everything.”
Middle English
bagge
English
bag
English, today
baggy
From bag + -y. bag comes from Middle English bagge. Middle English bagge, from Old Norse baggi (“bag, pack, satchel, bundle”) (whence also Old French bague (“bundle, package, sack”)); related to Old Norse bǫggr (“harm, shame; load, burden”), of unknown origin.
Etymology from Wiktionary, CC BY-SA