What this suffix does
The suffix -ism creates nouns that name a doctrine, belief system, movement, practice or characteristic. From "capital" you get "capitalism"; from "social" you get "socialism"; from "tour" you get "tourism". It covers three main groups: (1) ideologies and doctrines (capitalism, socialism, feminism); (2) practices and activities (tourism, journalism, vandalism); (3) style or behavioural traits (heroism, criticism, realism).