Infix: Definition and Examples

Audrey Hepburn - infixation
In the film version of My Fair Lady, Eliza Doolittle (played by Audrey Hepburn, dubbed by Marni Nixon) sings "Aow, wouldn't it be loverly? / Aow, so loverly sittin' abso-bloomin'-lutely still" (from the song "Wouldn't It Be Loverly" by Lerner and Loewe). (Warner Brothers/Getty Images)

An infix is a word element (a type of affix) that can be inserted within the base form of a word—rather than at its beginning or end—to create a new word or intensify meaning. The process of inserting an infix is called infixation. The most common type of infix in English grammar is the expletive, as in "fan-bloody-tastic." 

"[A]s the term suggests, [an infix] is an affix which is incorporated inside another word. It is possible to see the general principle at work in certain expressions, occasionally used in fortuitous or aggravating circumstances by emotionally aroused English speakers: Hallebloodylujah!...In the movie Wish You Were Here, the main character expresses her aggravation (at another character's trying to contact her) by screaming Tell him I've gone to Singabloodypore!" (George Yule, "The Study of Language," 3rd ed. Cambridge University Press, 2006)

How and When Infixes Are Used

Rarely used in formal writing, expletive infixation can sometimes be heard in colloquial language and slang though probably not in polite company. 

Infixation can make it into more casually themed press coverage (more likely in pop culture, as opposed to hard news), such as in "Prince William's former nanny [Tiggy Pettifer] has spoken of her joy at the engagement between the Prince and Kate Middleton, describing their union as 'fan-flaming-tastic.'" (Roya Nikkhah, "Prince William's Nanny Says Engagement Is 'Fan-Flaming-Tastic.'" The Telegraph [UK], Nov. 21, 2010)

And author Ruth Wajnryb has further examples—from literature, no less. "This linguistic phenomenon is also known as the integrated adjective. In fact, a poem of that name by John O'Grady (aka Nino Culotta) was published in the eponymously titled A Book About Australia, in which numerous examples of the integrated adjective appear: me-bloody-self, kanga-bloody-roos, forty-bloody-seven, good e-bloody-nough." ("Expletive Deleted: A Good Look at Bad Language." Free Press, 2005)

In English, additions normally attach to the end or start of a word, with prefixes and suffixes, such as pre- or -ed. There are even circumfixes, which attach to the front and the back, as in enlighten. In Austroasiatic languages in Southeast Asia and eastern India, the use of the infix is more common and not used just to create expletives, as in English. In fact, "English has no true infixes, but the plural suffix  -s behaves something like an infix in unusual plurals like passers-by and mothers-in-law" (R.L. Trask, "The Penguin Dictionary of English Grammar," 2000). 

Creating an Infix

Authors Kristin Denham and Anne Lobeck give a detailed explanation of where the infixes are inserted into a word:

"Native speakers of English have intuitions about where in a word the infix is inserted. Consider where your favorite expletive infix goes in these words:
fantastic, education, Massachusetts, Philadelphia, Stillaguamish, emancipation, absolutely, hydrangea
Most speakers agree on these patterns, though there are some dialectal variations. You likely found that the infix is inserted at the following points:
fan-***-tastic, edu-***-cation, Massa-***-chusetts, Phila-***-delphia, Stilla-***-guamish, emanci-***-pation, abso-***-lutely, hy-***-drangea
The infix gets inserted before the syllable that receives the most stress. And it cannot be inserted anywhere else in the word." ("Linguistics for Everyone: An Introduction." Wadsworth, 2010)