IPA: //ˈstraɪvər//
KK: /ˈstraɪvər/
A person who works hard to achieve their goals or improve themselves.
She is a striver who never gives up on her dreams.
Striver is formed from "strive" (from Old French *estriver*, meaning to struggle or exert oneself) and "-er" (meaning a person who). A striver is a person who struggles or makes an effort to achieve something.
Think of someone who is 'struggling' or 'exerting' themselves to reach a goal — that's what a striver does.