I often hear both used to describe a person or a person's action. The direct translations aren't the same, but from my experience, when used in context, I can't tell when to use one over the other. What are the differences?
夸张 (kuāzhāng) simply means Hyperbole, Exaggeration.
As in, your friend told a story that was too
Or if someone is acting ridiculous, crazy, or flamboyant (in a funny way, not in a mean way), you could say they're acting 夸张.
过分 (guòfèn), as you can tell from the two characters 过 (overstep), 分 (portion, point)... that they've overstepped their points/ or overstepped their boundaries.
Something helpful for me...
When the translations of words are similar (in the case of 夸张 and 过分), it always helps to break the word into parts as I described above. That helps for two reasons: