孤軍〔-军〕 gu¹ gwan¹ {gū jūn}

Alone (army)

孤軍作戰〔-军-战〕 gu¹ gwan¹ zok³ zin³ {gū jūn zuò zhàn}

Fighting alone

孤軍奮戰〔-军奋战〕 gu¹ gwan¹ fan⁵ zin³ {gū jūn fèn zhàn}

1. lit. lone army putting up a brave fight (idiom)
2. fig. (of a person or group of people) struggling hard without support