What is "prosiopesis"

n. (context grammar English) ellipsis of the beginning of a grammatical construction, common in informal speech and spontaneous written electronic communication, frequently occurring in stock phrases and interjections.

Prosiopesis (from Classical Greek, προσιωπησις, "becoming silent") is a term coined by Otto Jespersen for pronouncing a word or phrase without vocalizing its initial sounds. One example Jespersen gave is for "Good morning" to be shortened to "Morning". Jesperson introduced the idea in Language, Its Nature, Development, and Origin (ASIN B0007DEMMW; 1922); he also discusses it in The Philosophy of Grammar (ISBN 0-226-39881-1; reprint 1992). Prosiopesis is studied as a mode for originating interjections, which can shed light on their meaning.

See also aposiopesis.