1A junior — someone who joined a school, club, or workplace later than you, or who has less experience or seniority than you. The opposite of 先輩 (senpai).
新しく入った後輩に仕事を一から教えている。
I'm teaching a newly joined junior colleague everything from scratch.
大学の後輩から相談のメールが届いた。
I received an email asking for advice from a junior at my university.
部活の後輩たちは礼儀正しくて助かる。
The younger club members are polite, which is a big help.
彼は後輩の面倒見がよく、みんなに慕われている。
He looks after his juniors well and is well liked by everyone.