What is the difference between a metaphor and a hyperbole?

Answer 1

Metaphor is essentially based on comparison, suggestion of similarity. Hyperbole is based on exaggeration. But they are similar in that they both describe situations that are literally impossible. Metaphor: Mary is a cold fish (=not literally a fish, but an unemotional person, devoid of temperament); Hyperbole: Susan is as old as the hills (=very old; but no human can be literally as old as the hills); Mark has scores of girfriends (while in fact he may have three or four). Those two figures of speech can sometimes co-exist; if you say Mary is the coldest fish in the whole universe, that's metaphorical and hyperbolic at the same time.