A person dressed in their Best Bib And Tucker is wearing their finest outfit, their Sunday best. In the 1800s it was common for men of society to wear fashionable bibs to protect their morning and dinner suits from spills. Women of society wore lace or muslin, known as tuckers, tucked into the top of low cut dresses to protect their modesty. And so, couples dressed in their finest were known to have gone out in their “best bib and tuckers”. The phrase is now applied, as one, to either sex.