Spirit
Mind, Soul
noun
Spirit of the gods. This refers to both the "religious spirit" and the "spirit spirit." It's your spirit.
せいしん
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.
先生は「精神を養わなくてはならない」と言った。
My teacher told me that I must cultivate my mind.