noun
Refers to one's whole mental and physical energy, often in the context of pouring it into a task. Common in the phrase 精魂を込める (to put one's heart and soul into something).
彼はその作品に精魂を込めた。
He put his heart and soul into that work.
精魂尽き果てるまで戦った。
They fought until their spirit was completely exhausted.
Compound of 精 (せい, 'spirit, energy') and 魂 (こん, 'soul'). The combination emphasizes the totality of one's spiritual and physical energy.