Tmesis
Etymology
From Greek "tmēsis" (a cutting), from "temnein" (to cut). The figure literally cuts a word apart to wedge another one in.
noun · /tuh-MEE-sis/
The insertion of one word into the middle of another word or phrase.
What it names
"Abso-bloody-lutely" and "un-freaking-believable" — a handle for the way we crack a word open to shove emphasis inside it.
Example
"This is not, ladies and gentlemen, a-whole-nother question" is tmesis in action.
Related idea
The opposite maneuver from a portmanteau, which fuses two words into one; tmesis instead splits a single word open to admit an intruder.
See also