Yes. Set the wishlist to Invite only and the link you already sent stops working. Anyone who opens it gets a "No Access" page. If you'd rather remove the wishlist altogether, you can delete it. There's no separate button that switches off just the link.

Once it's private, the old link no longer opens the wishlist. From then on it's you plus anyone you invite by email.

The share link points at the wishlist itself rather than being a one-time code, so there's no "regenerate link" or "deactivate link" option. Switching to Invite only is how you cut people off. Worth remembering: if you later set it back to Anyone with the link, it's the same link as before, and the original recipients can open it again.

Once it's private, decide who should still get in and invite those people by email under your wishlist's access settings. See "How do wishlist privacy settings work?"

Deleting the wishlist removes it for everyone, and any reservations on it are cancelled at the same time. That one can't be undone.

Making a wishlist private doesn't change who can edit it. Editing access is a separate email invite, and visibility doesn't touch it. See "What's the difference between an editor, a guest, and someone reserving a gift?"