"What Is Love?" was written and composed by
Park Jin-young, who previously produced "
Signal", and it was arranged by Lee Woo-min "collapsedone", who co-produced "
Knock Knock" and "
Candy Pop". According to JYP Entertainment, the song is about "the love girls would dream about or imagine after learning about it through books, movies or dramas" and it has a bright melody and uptempo dance beat incorporating
trap. Tamar Herman of
Billboard described the song as having "retro
electro-pop styling" and an "addictive choral hook", with "digital quirks, sparkling chimes, and staccato'd percussion over the bubblegum melody". ==Music video==