Fist: noun
A four letter word with fingers is HAND or FIST.
A clenched hand/ fist. Source: Dictionary.com
hand
Another word meaning clenched is tighten.
Give
hand (usually called a ranch hand)
unit
unit
mime
Yes, the word 'fist' is a noun, a singular, common, concrete noun; a word for a hand with tightly closed fingers, a word for a thing. The word 'fist' is also a verb; to strike or grasp with a clenched hand.
hand, help, high, host, hunt
That is the correct spelling of "clenched" (closed, tightened).