"Fortnight" is a 1980s-inspired downtempo electropop, synth-pop, and new wave ballad built around a steady, pulsing synth bassline, leading to a concluding bridge featuring Swift and Malone's vocal harmonies.

The lyrics describe an emotionally impactful romance that lasts for two weeks: a woman in an unhappy marriage rekindles with a married ex-lover, and the two vow to escape to Florida.

In the video, Swift plays a mentally deranged patient portrayed in Victorian-gothic fashion who mourns a past relationship and relives its memories.

She continued working on The Tortured Poets Department while embarking on the Eras Tour in 2023, amidst media reports on her personal life including a breakup after a long-term relationship with Joe Alwyn and a short-lived romantic linking with Matty Healy.

[1][2] Swift announced The Tortured Poets Department at the 66th Annual Grammy Awards on February 4, 2024,[3] and unveiled the track listing via social media the following day.

[4] Swift brought the track to Malone's home studio in Los Angeles, and he recorded his background vocals and additional hooks for the bridge.

[32][34] According to Annie Zaleski, Swift sounds "seething and resigned", while Malone adds a sense of longing with his "earnest, buttery-smooth melodic counterpoints".

[b] Clash's Lauren Webb wrote that the track has a 1980s power ballad sensibility reminiscent of such artists as Roxette, Cutting Crew, and Phil Collins,[25] and The Guardian's Laura Snapes thought that the "burbling synths, booming drums and glazed backing vocals" evoked the music of the 1975.

[46] Swift said that the track features many characteristics that define The Tortured Poets Department, including themes of "fatalism, longing, pining away, lost dreams"[47] and hyperbolic and dramatic lyrics ("I love you, it's ruining my life").

[50][51][52] The short-lived yet emotionally impactful romance in "Fortnight" becomes the subject of many other album tracks, and its imagery of violence and death (such as the narrator fantasizing about murdering the ex-lover's wife and her own cheating husband) also recur on them.

[53][54][55] Rob Sheffield of Rolling Stone opined that the "1950s bad-marriage theme" of unhappy suburban marriages with cheating husbands and dutiful housewives "on the verge of nervous breakdowns" was reminiscent of Swift's songwriting for her past albums Folklore, Evermore, and Midnights.

[29] Clash's Lauren Webb and NME's Laura Molloy thought that the track displayed a new musical direction for Swift,[25][58] and The Irish Times' Finn McRemmond praised the "impossible catchy hook" despite the dreary theme.

John Meagher of the Irish Independent highlighted Malone's performance as more restrained compared to his usual "melodramatic" tendencies,[60] and Ed Power of The Daily Telegraph wrote: "His breathy singing voice dovetails surprisingly with Swift's angsty coo.

"[61] Billboard's Jason Lipshutz ranked "Fortnight" fifth out of the 31 tracks on the double album edition of The Tortured Poets Department, praising how Malone's appearance suits well with Swift's vocals and gives the bridge "subtle power and hangdog charm".

Callie Ahlgrim of Business Insider and deemed it uninventive and argued that it was too similar to Antonoff and Swift's previous collaborations, specifically calling it a derivative of Midnights.

[36] Mark Richardson of The Wall Street Journal deemed it mediocre,[22] and Paste and Our Culture Mag's Konstantinos Pappis criticized the sound as empty and bland.

[63][64] Variety's Chris Willman regarded the single as a good choice for pop radio, but he contended that it was "not much of an indication of the more visceral, obsessive stuff" for the album's remainder.

[69] The single debuted atop the Billboard Global 200, marking Swift's fifth number-one song and tying her with Bad Bunny for the most chart toppers among solo acts.

[82] Across other European territories, "Fortnight" reached the top five in Austria, Denmark, Germany, Switzerland, Belgian Flanders, Norway, Sweden,[83] Portugal,[84] Latvia,[85] Lithuania,[86] and Iceland.

[101][108] In the final scene, Malone calls from a telephone booth that Swift, in a sparkling flapper dress,[109] is on top of in the pouring thunderstorm rain, on an isolated cliff.

[98] According to many publications, Swift's character in the video evokes the protagonist of the 2023 movie Poor Things[e] and the scene of her being experimented on by mad scientists resembled Mary Shelley's 1818 gothic novel Frankenstein.

[f] In the French film magazine Première, Anthéa Claux compared the black-and-white cinematography and certain scenes to those of early-20th century German expressionist silent films: the close-up scene showing Swift's face and makeup evokes Metropolis (1927), and the mental facility setting with its bed suspended on the wall and distorted interiors resembles the settings of the The Cabinet of Dr. Caligari (1920).

Green, the video of "Fortnight" was part of Swift's foray into literary gothic, which was an important artistic endeavor that represented womanhood and critique of the self.