An amateur is a person who does something for enjoyment, not money, like an amateur who paints as a hobby but earns a living another way.
The adjective amateur often describes a pastime, like an amateur sports league that people join to get exercise and socialize together. Or it can have a negative meaning and describe something that's poorly done. If your guests leave your dinner table and stop for fast food on the way home, you may be ashamed of your amateur cooking skills. Amateur originated as a French word, meaning "lover of," not "expert."