"Unbridled joy" means experiencing extreme happiness or delight without any constraint or control. It is a state of pure and unrestricted joy. Full definition
Fortunately, Green's sequel doesn't have much interest in frustrations; this is a movie about unbridled joy, about transposing a cartoon veneer over a bleak human world. (indiewire.com)
Your cat will never wriggle with excitement when he catches sight of you, he won't jump up and down and lick you ecstatically, and he doesn't wag his tail with unbridled joy at the mention of the word «walk». (kristenlevine.com)
Laughing when I am struggling - or when I feel unbridled joy, too! (mindbodygreen.com)