The religious leaders of Jesus day made a big public display of their virtues of good works, praying and fasting. In contrast He said we should not draw attention to ourselves with our spiritual practices (Mt 6:1-18). Does my praying in public reflect my own times of heartfelt, private praying or is it a just a façade to try to impress those listening (Lk 20:47).
Teenage females provocatively reveal much of their bodies, as this gets them attention from males.
Nowadays this term is also used to describe behaviour that goes beyond what attracts attention to the indecent exposure of the genitals in public.