Crush

a Crush - to have a crush on:
A person (generally a human) you are attracted to. The words “to have a crush” can also be used as a verb, to describe a deep, intimate and strong desire to be with someone (physically but also in the sense of being in a relationship with that person). A “crush” is commonly not as strong and/or deep as love.

In the past the verb “to crush” meant to forcefully break, damage or compress something. It might just be a coincidence that the same word is used to describe a romantic feeling for someone.

When I was five, she used to be my crush!
But now I have a crush on another girl!