Idiom-a group of words established by usage as having a meaning not deducible from those of the individual words. (Ex. A piece of cake)
Onomatopoeia-the formation of a word from a sound associated with what is named (Ex. Boom or crack)
Hyperbole-exaggerated statements or claims not meant to be taken literally. (Ex.This guy escapes more times than Houdini)
I would say that this sentence is an hyperbole. This is because an idiom would be a form of figurative meaning that if different from the literal meaning. This is statement is bluntly advertised. There is no hidden meaning behind it. The word doesn’t resemble a sound either so it cannot be an onomatopoeia. I hope this helps
