淘汰

táotài
  1. to wash out
  2. (fig.) to cull
  3. to weed out
  4. to eliminate
  5. to die out
  6. to phase out

CEDICT

Entry Composition

1 淘 táo
  1. to wash (rice, sand etc in water to remove impurities)
  2. to dredge; to scoop out (sediment or waste)
  3. (dialect) to hunt for and buy (bargains or second-hand goods)
  4. (dialect) naughty; mischievous
2 汰 tài
  1. to discard
  2. to eliminate