A dark blue color.

Having a navy blue color.

Working class; engaged or trained in essentially manual labor. / Pertaining to the culture of blue-collar workers.

(idiomatic, music) The flatted 5th scale degree in the blues scale, also known as the flat five.

(colloquial, of a person) Having obvious bruises of the skin, typically from falling or being hit or punched.

A whale (Balaenoptera musculus), blue in color and the largest known living animal.

Any of various eucalyptus trees having blueish leaves, especially Eucalyptus globulus. / (slang, offensive) A person of sub-Saharan African origin, referring to the blue coloring around their gumline.

Being a blue-collar employee, an hourly worker.

Alternative form of true blue

(law) A law that prohibits or restricts commercial activity on Sunday.