laxative,
purgative, cathartic, emetic
elimination,
removal, eradication, expulsion, ridding, housecleaning (US, informal),
shakeup
get
rid of, eliminate, remove, eradicate, do away with, expel, expunge,
liquidate, oust, dismiss
pardon,
exonerate, absolve, forgive, excuse, shrive, atone for (formal)
antonym: castigate
(formal)
wash
out, cleanse, clean, flush out, clean up, purify, sluice