This character is a Other Symbol and is commonly used, that is, in no specific script.
The glyph is not a composition. Its East Asian Width is wide. In bidirectional text it acts as Other Neutral. When changing direction it is not mirrored. U+1F91B prohibits a line break after it, if it’s followed by an emoji modifier.
The CLDR project calls this character “left-facing fist” for use in screen reading software. It assigns these additional labels, e.g. for search in emoji pickers: fist, left-facing, leftwards.
This character is designated as an emoji. It will be rendered as colorful emoji on conforming platforms. To reduce it to a monochrome character, you can combine it with Variation Selector-15: 🤛︎ The character can be changed in appearance, if it is followed by an emoji modifier. See the Emojipedia for more details on this character’s emoji properties.
The Wikipedia has the following information about this codepoint:
A fist is the shape of a hand when the fingers are bent inward against the palm and held there tightly. To make or clench a fist is to fold the fingers tightly into the center of the palm and then to clamp the thumb over the middle phalanges; in contrast to this "closed" fist, one keeps the fist "open" by holding the thumb against the side of the index finger. One uses the closed fist to punch the lower phalanges against a surface, or to pound with the little-finger side of the hand's heel; one uses the open fist to knock with the middle knuckle of the middle finger.
Speakers of some English dialects may use the word "nieve" or "neef" to refer to a fist.