faithful servant; loyal retainer
Refers to a servant or retainer who is deeply loyal and trustworthy. Often used in historical or literary contexts.
彼は長年仕えた忠僕だった。
He was a faithful servant who had served for many years.
その老忠僕は主
The old loyal retainer kept his master's secrets.
Compound of 忠 (loyalty) and 僕 (servant). The exact historical derivation is uncertain, but the word has been used in Japanese to denote a devoted servant.