: The song is set in the C♯ Phrygian dominant mode, giving it a distinct sound often associated with Indian and Arabic music.
The song's live performances, particularly at the 65th Annual Grammy Awards, were met with intense scrutiny. Clad in crimson with "satanic" imagery, Smith and Petras drew complaints to the FCC and sparked accusations of "devil worship" from conservative commentators. However, Petras defended the creative choice as a commentary on her own experience with religion, stating the performance was inspired by the feeling of being excluded from traditional religious spaces as a trans person.
: It features a grinding bassline, Gregorian choir-like vocals, and metallic hyperpop synths reminiscent of producer SOPHIE.
"Unholy" made history on the Billboard Hot 100 as the first No. 1 hit performed by an openly non-binary artist and an openly transgender artist. This achievement was particularly monumental for Kim Petras, who had spent over a decade navigating the industry as a "niche" artist before this collaboration provided a "gateway" into her wider discography. For Sam Smith, it marked their first U.S. No. 1, proving their staying power and ability to evolve beyond the soulful ballads that defined their early career.
: The lyrics detail a secret affair at a strip club (the "Body Shop"), exploring themes of infidelity and liberation from "the clutches of others' secrets".
Musically, "Unholy" is a "sultry disco banger" and electropop track that draws from diverse influences, including: