• 奮起ふんき — to rouse oneself / rise to action
• 奮闘ふんとう — struggle / strenuous effort
• 奮発ふんぱつ — splurge / exert oneself generously
• 興奮こうふん — excitement

奮 combines 大 (big) with elements that suggest action and vitality. Ancient forms depicted birds flapping wings energetically, evoking the image of stirring into motion. It came to symbolize exerting effort, rousing courage, or being inspired to act.

彼かれは 奮闘ふんとうして 勝利しょうりを 得えた。
He fought hard and achieved victory.

卒業そつぎょうパーティーのために 奮発ふんぱつしました。
I splurged for the graduation party.