The compound "tell-all" is a modern English formation, originating in the mid-20th century. It directly and transparently combines the verb "tell," with its ancient sense of recounting a narrative, and the adjective "all," signifying completeness. The logic is literal: a narrative that "tells all" or reveals everything, leaving nothing concealed. This straightforward compounding reflects a trend in English for creating vivid, self-explanatory terms, particularly in journalism and popular culture, to describe works of sensational revelation. Its meaning evolved from the simple literal idea to specifically connote the disclosure of private, often scandalous, details.

Structure: tell (to relate) + all (everything) - tell: From Old English tellan (to count, relate, recount), of Germanic origin. In this compound, it functions as a verb root meaning "to relate or narrate." - all: From Old English eall (all, every, entire), of Germanic origin. In this compound, it functions as an intensifying adjective meaning "everything, the whole."