Pop rock is a hybrid of pop music and rock music that uses catchy pop style, with light lyrics over top of guitar- or piano- based songs. There are varying definitions of the term, ranging from it being classed as an "upbeat variety of rock music" to a subgenre of pop music or of rock music. Scholars have noted that pop and rock are usually depicted as opposites; the detractors of pop often deride it as a slick, commercial product along with advocates of rock who claim that rock music is a more authentic, sincere form of music.