What 츝 means
It is a Hangul syllable block, not a word by itself. Hangul groups letters, called jamo, into syllable blocks. 츝 has ㅊ first, ㅠ as its vowel, and ㅌ last; a Korean word supplies the meaning.
Hangul was completed in 1443 and explained in 1446 to make Korean easier to write for daily use than Classical Chinese. It coexisted with Hanja (Chinese characters used in Korean writing) and Idu (a method of writing Korean with Chinese characters); despite elite resistance, Hangul predominated by the late 19th century.
Questions people ask
1Why does 츝 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 츝
츝\CE1DCodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.