Baggy

wiktionary

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bag +‎  -y

Presumably back-formation from baggies (the plural), presumably a genericization of the brand name Baggies.

etymonline

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baggy (adj.)

"puffed out, hanging loosely" (like an empty bag), 1831, from bag (n.) + -y (2). Bagging in this sense is from 1590s. Baggie as a small protective plastic bag is from 1969. Baggies "baggy shorts" is from 1962, surfer slang. Related: Baggily; bagginess.