dirty joke

Idioms and Phrases

A smutty story, as in Teenagers love to tell dirty jokes . The use of dirty in the sense of “obscene” or “indecent” dates from the late 1500s, but its application to a joke began only in the 20th century. The same sense also appears in such expressions as dirty book , for a pornographic book; dirty old man , for a middle-aged or elderly lecher; and dirty word or talk dirty , for a lewd, offensive expression or sexually explicit conversation.