Claressa Shields and Laili Ali hasn’t been booked — despite big interest in the scrap — and there’s a simple reason why … the G.W.O.A.T. says the retired boxing star is SCARED!

TMZ Sports caught up with 30-year-old Shields in Los Angeles on Thursday — as she arrived at lunch with her boyfriend, rapper Papoose — when we asked about the status of the Ali fight.

“Layla and her representatives have told us no. Like, the answer is ‘no.’ She doesn’t want to fight. And that’s fine. I have no problem with that. I’m not upset. I mean, I wouldn’t fight me either. You know what I’m saying? I understand that she’s scared. I’m moving on,” Shields said.

“I thought that she was about all that talk. She wanted $15 million. I went and got the $15 million. And now it’s all this backpedaling. So, you know, congrats to her on whatever she’s doing. But I’m moving on with my career.”

Last month, Laila said Claressa would have to come up with a boatload of money if she wanted the retired boxing star to come back and scrap … something Shields’ told us she’d done.

But, alas, still no fight … and Claressa says she knows why.

“Layla is scared to fight me, and I would be scared to fight me, too. I get it.”

Shields also pointed to a change in women’s boxing … where the best fight the best (look no further than the Katie Taylor-Amanda Serrano trilogy).

“We’re in a generation now where the women fight each other. We don’t duck each other. And back in [Laila’s] generation, that’s all she did. So it is what it is.”

We asked Claressa if Laila’s behavior has caused her to lose respect for the 24-0 boxer (the answer is yes) … and Shields even evoked her rival’s late, great father.