If you describe someone as an individualist, you mean that they like to think and do things in their own way, rather than imitating other people. Individualists say that you should be able to wear what you want
Individualist means relating to the belief that economics and politics should not be controlled by the state. a party committed to individualist values. An individualist is a person with individualist views. They share with earlier individualists a fear of collectivism. someone who does things in their own way and has different opinions from most other people
If you say that someone is individualistic, you mean that they like to think and do things in their own way, rather than imitating other people. You can also say that a society is individualistic if it encourages people to behave in this way. Most artists are very individualistic