暗 dark

ANN Coulter with the sunny blonde hair, can't stand the sounds made by the darker ethnic groups.

memorize ★★☆☆☆
暗 (dark) + 記 (diary) = 暗記 (memorize)

assassination ★☆☆☆☆
暗 (dark) + 殺 (kill) = 暗殺 (assassination)

secret code number ★☆☆☆☆
暗 (dark) + 証 (proof) + 番号 (number) = 暗証番号 (secret code number)

your secret PIN number you use when you go to the ATM. This is different from a password you use on the internet - that's パスワード。