song-and-dance

The phrase "song and dance" emerged in American English in the late 19th century, directly from the world of vaudeville and theatrical entertainment, where a literal musical performance was a standard act. By the early 20th century, it began to be used metaphorically; a lengthy, elaborate stage routine became a figure of speech for any lengthy, often evasive, and unnecessarily complicated story told to persuade or distract an audience. The logic of the idiom hinges on the contrast between the simple, expected meaning (a literal performance) and its modern abstract usage, which implies a performative, insincere, or overly dramatic explanation meant to obscure the truth or create a diversion.

This is a fixed compound idiom. 'Song' originates from Old English sang, from Proto-Germanic sangwaz, related to singing. 'Dance' originates from Old French danser, of uncertain origin, possibly from a Frankish word. The hyphenated compound functions as a single lexical unit.