Index finger pointing upward, showing the back of the hand while doing so.
It is used in several meanings, including when it is meant to underline some statement and attract attention to it, to point out some fact, or to⚠️Warn someone about something important. Another popular meaning is when this emoji is used instead of the word "up", for example, to tell that its user is going to turn up the?Night, i.e. to go to the? Party.
Backhand Index Pointing Up was approved as part of Unicode 6.0 in 2010 under the name “White Up Pointing Backhand Index” and added to Emoji 1.0 in 2015.
U+1F446
? White up pointing backhand index