-asm / -ast alternates with the more common -ism / -ist. The difference is whether the Greek verb had an -a- or an -i- before the infinitival ending -zein. So enthousiazein 'to be inspired or possessed by a god' (cf. theos 'god'): enthousiasmos, enthousiastes. It's interesting that cineasm doesn't seem to be a word, at least in English. The only other -asm word I know is from the horror movie title Phantasm.