Knuckle tattoo

A knuckle tattoo is a kind of tattoo on the tops of a person's fingers, between the knuckles, commonly two groups of four-letter words or one eight-letter word.

[2] Some people also use their knuckles to tattoo drawings and images, sometimes in groups of four, such as the four symbols of a deck of playing cards.

[3] Robert Mitchum's character Reverend Harry Powell wears LOVE / HATE in the 1955 film The Night of the Hunter.

Professional wrestler CM Punk wears DRUG / FREE.

[6] In sailor tattoo traditions, deckhands may get HOLD / FAST as a charm to support their grip on rigging.