精一 is read as せいいつ (seiitsu) and means purity.
せいいつ
seiitsu
せいしんとういつ
concentration of mind
せいいっぱい
the best one can do
いっしょうしょうじん
striving to adopt ascetic practices for one's whole life
ぶしょうもののいっときばたらき
the ambition of the lazy does not last
そうじ
adherence to a vegetarian diet
せいしん
spirit (of a matter)
せいつう
(a boy's) first ejaculation
せいせん
careful selection
せいし
sperm
せいど
precision
せい
fine details
せいまい
rice polishing