Junior member of a group in Japanese arts; mentor.(noun)
Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License
Use "kohai" in a sentence
"Most of the dojo scenes are like that, depicting 20th century martial arts ettiquette but, very oddly, glossing over the sempai-kohai seniority structure."
"He is the sempai (guide) to Snipes's kohai (the younger protege), and our instructor in the mysteries of the East."
"Sort of like a Japanese college acquaintance of mine who would use the English pronoun 'you' when talking to me in Japanese, because none of the implications of omae, kimi, anata, otaku, onore, kisama, etc., were quite appropriate to kohai-senpai relationship."