Refers to a closed hand, often in the context of fighting, striking, or making a determined gesture.
He raised his fist in anger.
He clenched his fist in anger.
The boxers touched fists before the match.
He punched his opponent with his fist.
The player thrust his fist into the air after scoring the goal.
拳 is the general word for a clenched fist in any context, while グー specifically names the fist shape used in じゃんけん.
拳 is the plain, neutral word for a fist, while 鉄拳 stresses its hardness and force, like an 'iron fist'.
Standard kanji spelling.
Kana spelling is common in informal writing or when the kanji is not needed.
The kanji 拳 is a phono-semantic compound with 手 (hand) and a phonetic component, originally meaning 'fist'. The reading こぶし is a native Japanese word of uncertain origin, possibly related to 小節 (small joint/knuckle).