1920s. From Arabic al-salafiyya (collective plural), the name of a strictly orthodox Sunni Muslim reform movement founded in Egypt in the 19th cent. from salaf (collective plural) predecessors, ancestors, (specifically) the first generations of Muslims, considered paragons of their faith, as well as (in extended use) later exemplary Muslims (from salafa to be past, to precede, to antecede) + -iyya, suffix.