The suffix -ist attaches to the end of words to create nouns that describe people. It usually means “a person who does something” or “a person who believes in something.”

When you add -ist to an activity or skill, you get someone who practices it. A pianist plays the piano. A chemist studies chemistry. An artist creates art. A cyclist rides a bicycle. The suffix turns the thing itself into the person who does it.

The suffix also creates words for people who follow particular beliefs or systems. A capitalist believes in capitalism. An optimist tends to see the positive side of things. A perfectionist tries to make everything perfect.

Sometimes -ist describes someone who specializes in a field. A biologist specializes in biology. A geologist studies rocks and earth formations. A novelist writes novels.

Notice how the suffix works: you start with the root word (piano, art, cycle, optimism) and -ist transforms it into the person connected to that word. The spelling sometimes changes slightly when you add it (biology becomes biologist, not “biologyist”), but the pattern stays consistent. Understanding -ist helps you figure out thousands of English words. When you see an unfamiliar word ending in -ist, you can usually guess it means “someone who does or believes in whatever came before.”