A classic smiley, turned upside down. Implemented as a flipped version of π Slightly Smiling Face on most platforms.
Commonly used to convey irony, sarcasm, joking, or a sense of goofiness or silliness. Its intent can be similar to the bemused Oh well! of π€· Person Shrugging or the shruggie emoticon, ¯\_(γ)_/¯.
Microsoft's design previously featured a full-toothed grin.