1.
the same kind, same type
Things or people that belong to the same category or share common characteristics.
この二つは同類の製品だ。
These two are products of the same type.
同類の問題が他の部署でも起きている。
Similar problems are occurring in other departments too.
過去の研究から同類の事例を集めて分析した。
We gathered and analyzed similar cases from past research.
2.
fellow, accomplice, birds of a feather
A person who shares the same (often negative) traits or associations. Frequently used with a critical or dismissive nuance.
あいつらは同類だよ。
Those guys are birds of a feather.
あの政治家も結局は同類だと思われている。
That politician is also seen as being cut from the same cloth in the end.
彼と一緒にいると同類だと思われるから、距離を置いた方がいい。
If you hang around with him, people will think you're the same sort, so you'd better keep your distance.
USAGE:
Sense 1 is neutral and used in academic or analytical contexts. Sense 2 carries a negative nuance, implying guilt by association or shared bad traits. The expression 同類相憐れむ (birds of a feather commiserate) is a well-known saying.
COMMON COLLOCATIONS:
- 同類の製品: products of the same type
- 同類の問題: similar problems
- 同類と見なす: to regard as the same kind
SIMILAR WORDS:
同類 emphasizes shared category or traits (often negative for people). 同種 is more neutral and technical, meaning "same species" or "same type." 仲間 means "companion" or "peer" with a positive or neutral nuance.