noun
partisan spirit; factionalism
Refers to a narrow-minded loyalty to one's own faction or party, often with a negative connotation of prejudice or stubbornness.
彼の意見は党派根性に過ぎない。
His opinion is nothing more than partisan prejudice.
その議論は党派根性が強く、建設的ではなかった。
The discussion was heavily factional and not constructive.
Compound of 党派 (tōha, 'faction, party') and 根性 (konjō, 'disposition, spirit'). The exact historical derivation is uncertain, but the term likely emerged in political discourse to criticize narrow partisanship.