Teacher
Sensei
noun
Previous life... So we're talking about someone who has a previous life, or maybe previous life experience? When you have previous life experience, you can teach others about it, making you qualified to be some kind of teacher.
先生 is often used for school teachers, but it's also used to show respect to doctors, lawyers, authors, and other respected experts. It's used as a standalone word or a name ender like トム先生.
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.
クラスの先生
a class teacher
他の先生
other teachers
ピアノの先生
a piano teacher
先生の本
the teacher's book
先生のアドバイス
the teacher's advice
先生のおはなし
the teacher's story
先生がおっしゃる
the teacher says
先生がいる
there's a teacher
先生がくれる
the teacher gives
先生たち
teachers
先生方
teachers
先生どうし
fellow teachers, between teachers
花先生
Hanna-sensei, Dr. Hanna
アーロン先生
Aaron-sensei, Dr. Aaron
本田先生
Honda-sensei, Dr. Honda
先生はおもしろい
the teacher is funny
先生はやさしい
the teacher is kind
先生はすごい
the teacher is amazing
先生にそうだんする
to ask a teacher for advice
先生になる
to become a teacher
先生にいただく
to receive something from the teacher
先生は「おはよう」といった。
The teacher said "good morning."
あの女の人は、田中先生です。
That woman is Tanaka-sensei.
コウイチは、わたしの人生の先生だ。
Koichi is my teacher in life.