here's your answer and I hope I helped you.
This is most evidently a metaphor. The thing to keep in mind when analyzing literature/poetry is that if you see figurative language making comparisons/drawing parallels between two differing things--instances where the meaning is not literal such as how injustice is not really a fire and has no flames--it's a safe bet you'll have on your hands a metaphor.
Prefixes: Ex, Im, Tele, or Trans.
The way that catharsis is related to Romeo and Juliet is that the moment of catharsis in the play occurs when Romeo and Juliet kill themselves.
Catharsis is emotional discharge after something tragic has happened. The audience usually cries and feels pity after something sad has happened, and that moment is called catharsis. So naturally, when these two young people kill themselves, it is quite sad and the audience feels strong emotions after their death.
