Word: kohai
Part of speech: Noun
Syllables: ko
hai
Definition: An underclassman or younger student.
Morphemes:
Affix: kohai
Language: en
PoS: Noun
Meaning: An underclassman or younger student.
Etymology Compounds: Affix: 後輩
Language: ja
Decoded: Hou Bei 
Meaning: later cohort