From Wiktionary, the free dictionary
From prison + -wear.
prisonwear (uncountable)
- Clothes to be worn by inmates of a prison.
2014, Roger Frankham, “USA”, in Bite Size World: Eating My Way Around the Planet, Cirencester: Mereo, →ISBN, part three (North America), page 181:Convicts in striped prisonwear collect trash by the roadside, watched over by their guards.