A red cross mark emoji is the symbol of interdiction and multiplication. This symbol is generally used to indicate things that are negative or restricted. It can be used to express errors and warnings.
NOTE: Cross Mark was accepted in 2010 as part of Unicode 6.0 and labeled Emoji 1.0 in 2015.
❌ Cross Mark
:x: (Github, Slack)Cross Mark Emojiemoji copy and paste