0 a lack of shame, especially about something generally considered unacceptable: --
With her customary shamelessness, she shakes her curls and puffs out her thin lips.
Promiscuity, shamelessness, and corruption ruled supreme.
The jury were astounded at the shamelessness of his views about adultery.
Her absolute shamelessness means she can get away with things others simply can't.
Nobody would have the shamelessness to do such a terrible thing.