What 떶 means
The block supplies a syllable; the word supplies its meaning.
The 떶 jamo are three Korean letters, or component letters: ㄸ, ㅓ, and ㅈ. Together they form one syllable block; the surrounding word determines how it is read and what it means.
The Korean alphabet, Hangul, was created in 1443 to make Korean easier to write and learn; its purpose and design were explained in 1446. Earlier traditions such as Idu, Gugyeol, and Hyangchal adapted Chinese characters to write or read Korean. Those dates describe the history of Hangul, not the origin of this individual block.
Why does 떶 split into jamo?
It may be decomposed text or a display limitation.
Unicode can represent a Hangul syllable as one precomposed block or as an equivalent sequence of component letters. An input method or font with Hangul shaping support can compose or display those parts as a block; other contexts may show the jamo separately. The syllable remains the same.
Neutral as written Korean; by itself, 떶 is fragmentary rather than a conventional chat reaction.
Do not read a mood into an isolated 떶.
What it means when someone sends it to you
2 readingsQuestions people ask
1Why does 떶 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 떶
떶\B5B6Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.