Tmesis is a rhetorical and poetic device involving the insertion of one or more words into the middle of a compound word or phrase for emphatic, rhythmic, or humorous effect, such as “abso-bloody-lutely” or “what-so-ever”; in classical poetry, tmesis often split prefixed verbs (e.g., “dis-regard” instead of “disregard”) to meet metrical needs or create dramatic pause, while in modern usage it conveys colloquial vigor, emotional intensity, or linguistic playfulness, allowing poets to manipulate syntax for sonic surprise or expressive exaggeration.

Word division by inserting another between parts. Example: "what person soever" for "whatsoever person." Rare, archaic device. Creates emphasis, altered rhythm. Historical interest mainly.