You might remember the meaning of the character 喃 with this easy mnemonic:
If you open your mouth (口) and mumble in repetition ten (十) times, you can memorize the password of this down box (冂). Or you can always choose to tattoo it into your eyebrows (丷), but when your eyebrows are dry (干), you won't be able to see the password.
Using mnemonics to remember the meaning of Chinese characters like has a huge impact on how long to learn Mandarin it takes.