Combining them, 出师表 (chū shī biǎo) literally means “A Memorial (表) for Dispatching (出) the Army (师).”
The 出师表 is a cornerstone of Chinese cultural literacy, revered for both its literary elegance and its moral weight. Written by Zhuge Liang (诸葛亮) to the second emperor of the Shu Han kingdom, Liu Shan (刘禅), it embodies the Confucian ideal of the loyal minister (忠臣, zhōngchén). The context is crucial: Zhuge Liang was entrusted by the dying first emperor, Liu Bei, to look after his young, inexperienced son and guide the kingdom. This memorial was written before Zhuge Liang embarked on his Northern Expeditions, a series of high-stakes campaigns against the rival kingdom of Wei. It's a mixture of strategic military briefing, political advice, and a deeply personal expression of his commitment to fulfilling his promise to the boy's father.
While you won't hear “出师表” in everyday casual conversation, it is frequently used as a powerful metaphor in more formal or literary contexts.