fake breasts; artificial breasts
Slang term for breast forms, padded bras, or surgically augmented breasts. Often used in casual or humorous contexts.
See also: 偽乳
There's a rumor that idol has fake breasts.
I bought fake breasts for cosplay.
Compound of 偽 (にせ, fake) and パイ, a slang abbreviation of おっぱい (breasts).