Adult Onesie Pajamas

pajamas
A suit of loose pants and jacket or shirt for sleeping in
A pair of loose pants tied by a drawstring around the waist, worn by both sexes in some Asian countries
(pajama) a pair of loose trousers tied by a drawstring around the waist; worn by men and women in some Asian countries
(pajama) (usually plural) loose-fitting nightclothes worn for sleeping or lounging; have a jacket top and trousers
Pajamas, also spelled pyjamas (see also spelling differences) can refer to several related types of clothing. The original paijama are loose, lightweight trousers fitted with drawstring waistbands and worn in South and West Asia by both sexes.

onesie
An infant's one-piece close-fitting lightweight garment, usually having sleeves but leaving the legs uncovered and fastening with snaps at the crotch
An infant bodysuit is a garment designed to be worn by infants much like a t-shirt; they are distinguished from t-shirts by an extension below the waist, with snaps or Velcro that allow it to be closed over the crotch.
A one-piece garment for an infant or small child, generally worn over a diaper
(Onesies (game)) Jacks (sometimes called jackstones, jackrocks, fivestones, onesies, knucklebones, or snobs) is a playground game for children.

adult
Of or for adult people
a fully developed person from maturity onward
(of a person or animal) Fully grown or developed
(of animals) fully developed; "an adult animal"; "a grown woman"
any mature animal
Emotionally and mentally mature