-ist  suffix forming personal nouns denoting: 1 adherent of a system etc. In -ism: (marxist; fatalist). 2 person pursuing, using, or concerned with something as an interest or profession (balloonist; tobacconist). 3 person who does something expressed by a verb in -ize (plagiarist). 4 person who subscribes to a prejudice or practises discrimination (racist; sexist). [greek -istes]