Basically love at first sight.
"Since the first day we met, I had an instant crush on him."
Instead of being with a different girl/boy all the time, they have a crush on a different girl/boy all the time.
Person 1: That girl is such a hoe.
Person 2: No she's not. She never dates anyone so she's not a hoe.
Person 1: But she has a crush on someone new like every week.
Person 2: That just makes her a crush hoe not an actual hoe.
A girl so cool even (straight) girls could have a crush on her.
Often used as a concept in Kpop, where a girl group would showcase cool but feminine attitude and style.
Person 1: Do you remember when Jeongyeon from Twice had really short hair?
Person 2: gosh, yes, she’s so pretty. She’s the definition of girl crush.
Someone you see in a public place and you have a major attraction to them. Could see a future with them but you chicken out.
Friend 1: Yo I just had a Walmart crush
Friend 2: What the heck is a Walmart crush? Are you high?
The person you had a crush on when you were very young
I remember watching Get Smart as a three year old. Agent 99 was my "toddler crush".
When an adult has a strong fondness or admiration for a child they know but aren't related to, like a daughter's friend. Analogous to a boy crush or a girl crush, it isn't necessarily romantic or sexual in any way.
A part of me really wanted to get to know this child better but I was certain that people would assume a child crush meant more than it really does.