cardboard

plural cardboards

1. countableuncountableA wood-based material resembling heavy paper, used in the manufacture of boxes, cartons and signs.
2. countablefigurativelyuncountableSomething flat or insubstantial.

   2 more examples

   In my experience, one of the most vital times in the life of a piece of fiction is when a character begins to speak, timidly and softly, in one's head. Honest and true books get written when the author feels free to coax and invite that character in. If the author's response to that small voice is instead to submit it to a test: "Are you: black/white/gay/straight/male/female/Christian/Jewish/old/young/politically correct" the character will probably turn around and leave or else turn into cardboard.

   1980 February 9, Andrea Loewenstein, “James Baldwin and His Critics”, in Gay Community News, volume 7, number 28, page 10

   According to these keyboard warriors, the young men and women who survived the shooting are part of a big hoax, are liars, are mere cardboard cutouts – “crisis actors” who roam the country looking for mass shootings from which to promote their anti-gun message – all being pushed forward by the giant liberal machine that is Hillary Clinton’s robot attack army.

   2018 February 21, Jeff Pearlman, “Parkland students, ignore the idiots”, in CNN

3. countableuncountableSynonym of African nutmeg (“Pycnanthus angolensis”).

   Synonyms: African nutmeg

1. Made of or resembling cardboard.

   The thing really looked quite cardboard.

   1973, Journal of Black Poetry, number 17, page 27

   1 more example

   MUMMER 3 pulls out an inflated cushion with a very cardboard crown on it.

   2001, Liz Lochead, “Mary Queen of Scots Got Her Head Chopped Off”, in Cairns Craig, Randall Stevenson, editors, Twentieth-Century Scottish Drama, Edinburgh: Canongate Books, →ISBN, page 501

2. figurativelyFlat or flavorless.

   The worst of the thing, however, is that the enormity, such as it is, happens to be of a very cardboard and tinsel character.

   1868, Arthur William A'Beckett, “Painted Ships and Painted Oceans”, in The Tomahawk, page 114

   2 more examples

   […]a conventional historical drama -- one of those event-crammed sagas featuring a beautiful, plucky heroine, a mysterious, elusive lover and a cardboard supporting cast of thousands.

   1999 November 2, Michiko Kakutani, “Books of The Times: A Single Girl Takes On the California Frontier”, in The New York Times (E section), New York, N.Y.: The New York Times Company, →ISSN, →OCLC, page 7

   While Lensky’s character is quite cardboard, Onegin’s manipulations and lack of ability to call off the duel because he fears society’s jibes, Lensky’s youth and naivety, and Tatiana’s reaction to the duel lend the event its gravity.

   2008, Katya Hokanson, Writing at Russia's Border, page 122