汰 - washing, sieving, filtering

not writing or contacting for a while; neglecting (failing) to write (call, visit, etc.); long silence

sexual selection

insane behavior; madness

(committing, resorting to) an act of violence

out of the question; preposterous

social selection

sexual selection

artificial selection

personnel reduction

bloodshed

weeding out; elimination (e.g. of unneeded employees); culling; selection

going public (with a matter); becoming public knowledge