寝返る[ねがえる] (negaeru)

部下ぶかが 敵てきに 寝返ねがえった

The subordinate betrayed his/her ally to the enemy.

寝返る危険性もあった。

They adamantly refused to switch sides.

細川尹賢、晴元方に寝返る。

Tadakata HOSOKAWA defected to Harumoto's side.

彼は寝返ることができるようになった。

He came to be able to roll over in his sleep.

しかし三好三人衆の調略にのり池田知正とともに三好氏に寝返る。

But he went over to the Miyoshi clan along with Tomomasa IKEDA, following a stratagem of the three chief retainers of the Miyoshi clan.

こいつ、さっきまで 俺おれの 相棒あいぼうだったのに、もう 寝返ねがえりやがった。

This rat, up until just now he was my partner and now he's gone and turned on me.

関ヶ原の合戦では当初は西軍につくが、主戦場で小早川秀秋に同調して東軍に寝返る。

In the Battle of Sekigahara, he initially fought for the Western Camp, but later, on the main battle field, he followed Hideaki KOBAYAKAWA's example and defected to the Eastern Camp.

天正6年（1578年）伊東氏の高鍋城城主・落合兼朝が島津家に寝返ると、忠智は財部城主に任命される。

In 1578, when Kanetomo OCHIAI, the lord of Takanabe-jo Castle on the side of the Ito clan shifted sides to the Shimazu family, Tadatomo was appointed the lord of Takarabe-jo Castle.

彼らの多くは、似たような状況下に置かれた農民達に同情的な者も多く、一揆側に寝返る者が現れる始末だった。

Many of such samurai were sympathetic to peasants who lived in the similar conditions, and eventually, some of them even went over to the side of ikki.

このとき東信濃から西上野に勢力を保っていた真田昌幸は北条方に属するが、徳川が東信濃に侵攻してくると徳川方に寝返る。

At this time, Masayuki SANADA who had influence from eastern Shinano to Nishiueno belonged to the Hojo side, but when Tokugawa invaded eastern Shinano, he switched to the Tokugawa side.

ところが、孝景は、文明_(日本)3年（1471年）5月、将軍義政及び細川勝元から、守護権限行使の密約をもらって東軍に寝返る。

However, in May 1471, he was offered a secret agreement on authorization to act as regional military governor by Shogun Yoshimasa and Katsumoto HOSOKAWA, and shifted sides to join the Eastern squad.