washing, sieving, filtering, weeding out, luxury
汰 centers on separating what is wanted from what is not: washing away impurities, sieving, filtering, or weeding out. The luxury sense is a separate, less common application that likely developed from the idea of selecting only the best.
汰 combines 氵 (water) with 太, which likely contributes the sound and the idea of excess or largeness. The original sense may relate to washing away excess or impurities with water.
Water 氵 beside 太 (fat, great) suggests washing away the excess to purify. Imagine using water to sieve out the fat and filter what remains.
For タ, picture a tub of water used for washing: tub -> タ, and the water radical 氵 reinforces the washing scene.
affair; state; incident; issue; matter
not writing or contacting for a while; neglecting (failing) to write (call, visit, etc.); long silence
weeding out; elimination (e.g. of unneeded employees); culling; selection
news (from someone); word; letter; tidings; contact
going public (with a matter); becoming public knowledge
having nothing to do; having time on one's hands (and not knowing what to do); being at a loose end; being bored
salted rice-bran paste for pickling
personnel reduction
artificial selection
money talks; money is the key that opens all doors; even the Buddha's verdict is (decided by) money
secret government business
bloodshed
beginning (developing into) a quarrel (a fight, an altercation)
money talks; money is the key that opens all doors; money is the best lawyer in hell; even the verdict of hell is determined by money
(imperial) words
sexual selection
reorganizing an industry or enterprise and weeding out redundant workers; readjustment and retrenchment
(committing, resorting to) an act of violence
sound judgment; sane decision; act performed with a clear mind
insane behavior; madness