expression, suru verb (irregular)
throw away as useless; scrap; discard
Used for physical objects, plans, or ideas that are deemed worthless and discarded. Often implies treating something as wastepaper.
古い書類を反故にした。
I threw away the old documents as useless.
その案は結局反故にされ
That plan was eventually scrapped.
expression, suru verb (irregular)
make null and void; renege on; annul; revoke
Used for promises, agreements, contracts, or decisions that are treated as if they never existed. Stronger than simply canceling; implies disregard or betrayal.
彼は約束を反故にした。
He reneged on his promise.
その契約は一方的に反故にされた。
The contract was unilaterally annulled.