“Fiction,” we all know, is something that is not true. So is “a lie.” But they’re not quite synonyms: Fiction is usually a benign lie, like making up a story to entertain others, rather than telling someone that no, I don’t know anything about closing lanes on a bridge.
When coming up with adjectives for those made-up things, we have many to choose among: “fictional,” “fictitious,” or “fictive,” or even “factitious.” Choose wisely, or risk saying something you don’t mean.
“Fictitious” is the broader term, and the first one to appear in English, in 1615, according to the Oxford English Dictionary. Anything made up can be “fictitious,” and the only connotations the word takes are that whatever attached to it is plain fake.
“Fictional,” which traces only to the early 19th century, is the adjective used most often in reference to literature, movies, and the theater. “Riverside, IA, is the home of the fictional Capt. James T. Kirk of the USS Enterprise” lets you know the character is made up. In a movie review recounting art-imitates-life parallels, the phrase “the film’s plot included a thinly veiled swipe at her ex-husband via its fictional director who has an affair with an actress” lets you know the character is fake, but not really made-up.
“Fictive” implies not just invented, but inventive with a certain creativity to make a point. An artist might create a composite villager, for example, whom reviewers might call “a fictive villager,” a character to represent the village in a way the artist has manipulated, often just as Everyman. Yes, it is both fictitious and fictional, but the motive is different: The protagonist in a novel may be “fictive,” but most of the other characters are probably just “fictional,” created to support the protagonist and not to be standouts on their own. A New York Times article also noted that anthropologists describe extended networks of close-knit but unrelated people as “fictive kin.”
The use of “fictive,” however, has grown exponentially in the past 40 years or so, possibly as writers adopted it as shorter and more “literary.” But it is not always accurate. A “fictive rehearsal room” created for the movie Saving Mr. Banks was trying to capture and concentrate the conditions under which Disney movies were often created. But a local library holding a “fictive detective mystery night” is probably just trying to save a few letters.
“Factitious,” however, is not just fake, but created by human intervention, often through contrivance or other manipulation. (“Factitious air,” for example, is any gas produced in a chemical experiment.) It adds a motive, often sinister, to the fabrication. Fittingly, it is the least used of the adjectives, and it should remain thus, for its air of accusation.
Garner’s Modern American Usage has a handy guide to all these falsities:
These forms overlap to a great degree, but they have undergone some useful differentiation. Fictional = of, relating to, or having the characteristics of fiction … Fictitious = (1) false, counterfeit; or (2) imaginary. … Fictive = having the capacity of imaginative creation (fictive talent). Apart from this narrow sense, fictive is a needless variant of both fictional and fictitious.
You just can’t make this stuff up.