oppress, v. [burden], [overwhelm], aggrieve, [tyrannize], [persecute], [overpower].
oppression, n. [tyranny], [persecution], [extortion], [hardship], [severity].
oppressive, a. [rigorous], [tyrannical], [extortionate], burdensome.
oppressor, n. [tyrant], persecutor, [extortioner].
option, n. [choice], preference, election, [discretion], alternative. Antonyms: [constraint], [coercion], [compulsion].
optional, a. [discretional], elective. Antonyms: [compulsory], coercive, [obligatory].
oral, a. [spoken], [verbal], parole, vocal, nuncupative.
oration, n. declamation, rhetoric.
orator, n. declaimer, rhetorician.
oratorical, a. rhetorical, eloquent, declamatory.