同類|どうるいdourui[0]heiban (flat)

1. no-adjectivethe same kind; accomplice; partner
   石炭せきたんは化学的かがくてきにダイヤと同類どうるいである。↗

   Coal is chemically allied to diamonds.

• Synonym同種どうしゅNeutralSame kind or species; used mainly for classifying living things and objects. Unlike 「同類」, it has no 'accomplice' sense.
• Synonym同士どうしNeutralUsed as a suffix meaning 'each other', as in 「友達同士」; it stresses the mutual relationship between those involved.
• Related仲間なかまNeutralCompanions or mates; the most common everyday word, with a sense of closeness. It matches the 'companion' side of 「同類」.
• Related同志どうしNeutralPeople who share the same ideals or aspirations; it stresses a common cause and carries a positive tone.
• Related朋輩ほうばいWrittenFellows under the same teacher or colleagues; written and old-fashioned. It lacks the 'same kind' sense of 「同類」.
• Related同輩どうはいNeutralPeople of equal status or standing; rare, especially in writing, and free of the 'accomplice' nuance.
• Antonym別種べっしゅNeutralThe opposite of 「同類」: a different kind or species, as in 「別種の生物」.
• Antonym異類いるいNeutralThe opposite of 「同類」: different kinds, and by extension non-human beings such as yōkai.

For 'the same kind', use 「同類」 or 「同種」; for companions, 「仲間」 is the everyday word. 「同類」 also means an accomplice, as in 「彼も同類だ」, negative depending on context. 「同士」 is a suffix for 'each other', 「同志」 implies shared ideals, and 「異類」/「別種」 mean different kinds.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 同おなじ種類しゅるい。
2. 同おなじ仲間なかま。