1. Related to a particular skill or profession:
* Artist: Someone skilled in a particular art form.
* Pianist: Someone who plays the piano.
* Typist: Someone who types.
* Pharmacist: Someone who prepares and dispenses medications.
2. Characterized by a particular quality:
* Fatalist: Someone who believes in fate.
* Idealist: Someone who believes in perfect ideas.
* Realist: Someone who accepts things as they are.
* Optimist: Someone who is hopeful and positive.
3. Relating to a particular place or object:
* Aeronaut: Someone who travels in an aircraft.
* Bibliophile: Someone who loves books.
* Cosmonaut: Someone who travels in space.
4. Related to a specific scientific field:
* Geologist: Someone who studies the Earth.
* Zoologist: Someone who studies animals.
* Physicist: Someone who studies physics.
5. Sometimes used as a playful or informal ending:
* Foodie: Someone who loves food.
* Techie: Someone who is skilled in technology.
* Fashionista: Someone who is interested in fashion.
It's important to look at the whole word to determine the meaning of the suffix "-ast" in a particular case.