Spirit, Health
Noun and な adjective
げんき
お父さんは、元気ですか。
How is your father?
かなちゃんは、元気いっぱいですね。
Kana is full of energy.
彼は元気そうに見えたが、実はひどい下りだったらしい。
He seemed fine but apparently he had a bad diarrhea.
What is the origin of your energy? It is your spirit and health (though this vocab word also means energy as well).
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.