dirty

(waterleft) + (pirate's hook)
★★★★☆
6 strokes
BOOBOO: Although your books will tell you this means 'kitanai,' kitanai is 99.9% written in hiragana, so don't bother.

Onyomi

O

Mnemonic

OH shit, get some water! That pirate's hook of yours is just nasty and filthy and dirty as -- where have you been putting that hook??? (up Peter Pan's butt is the answer; we both know this)

Kunyomi

( ) よご*す to make something dirty
★☆☆☆☆
( ) よご*れる to be polluted. Both literally, like a dirty shirt, and metaphorically, like an untouchable person.
My friend said this is an important 'cultural code word,' because in Japan if someone is a dick to you and you fight back in public, you are considered 汚れた, That is, you're linked publicly with that person even if you were defending yourself. That's why girls don't punch guys trying to hassle them. I'm not sure it's true what my friend said, but she's pretty right-wing so she would never make up somethin CCW
★★★★☆

Jukugo

汚染(おせん)

pollution/contamination ★★☆☆☆
(dirty) + (dye) = 汚染 (pollution/contamination)

pollution OR contamination. (BOOBOO : If you want to say "environmental pollution," you have to use 汚染、 not 公害。)

Synonyms

corruption, bribery
堕落    汚職    賄賂    横領    使い込む   
pollution
汚染    公害