What does antithesis mean?
The definition of antithesis
An*tith”e*sis, n.; pl. Antitheses.
Etym: [L., fr. Gr. Thesis.]

1 (Rhet.)
An opposition or contrast of words or sentiments occurring in the same sentence; as, “The prodigal robs his heir; the miser robs himself.” “He had covertly shot at Cromwell; he how openly aimed at the Queen.”
2 The second of two clauses forming an antithesis.
3 Opposition; contrast.