What 믊 means
It is one Hangul syllable, not a complete Korean word.
ᄆ is the starting consonant, ᅳ the vowel, and ᆱ the two-consonant ending. These Hangul jamo are basic letters joined into a syllable block.
Hangul was made to write Korean in syllable blocks. The earliest recorded notice of Hunminjeongeum is from late 1443; a 1446 explanatory book describes the script's purpose and syllable design. Unicode can encode a syllable as one block or a jamo sequence; fonts may shape and position its parts differently.
What it means when someone sends it to you
2 readingsQuestions people ask
1Why does 믊 show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
How to type 믊
믊\BBCACodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.