I mean, here's just the two explanations on google, i think they explain it well enough Fiery - consisting of fire or burning strongly and brightly. Burning - on fire. I mean they are very similar, almost synonyms, so don't worry too much about it, hope i helped, if ya need any help or anyone to talk to, you know where to find my profile

Thank you, Michael. I understood. I think there also can be some words which mean almost the same. At least I leant that fiery and burning are almost the same but fiery is more strongly on fire.