noun

antithesis – the exact opposite of something or someone
– the state of two things that are directly opposite to each other

-the rhetorical contrast of ideas by means of parallel arrangements of words, clauses, or sentences

-the second of two opposing words, clauses, or sentences that are being rhetorically contrasted

Learned about this in Speech today and thought i would interesting to look up this particular word because of the many times it has been used in history.
One example being “Ask not what your country can do for you; ask what you can do for your country.” – John F. Kennedy