A hand with the fingers clenched or curled inward.
“The boxer's fists rained down on his opponent in the last round.”
The pointing hand symbol ☞.
verb
To strike with the fist.
“...may not score a point with his open hand(s), but may score a point by fisting the ball. Damian Cullen. "Running the rule." The Irish Times 18 Aug 2003, pg. 52.”