noun, na-adjective
single-minded loyalty; steadfast devotion to one's master
Describes unwavering, wholehearted loyalty, typically in a feudal or hierarchical context. Often used with に as an adverbial phrase.
彼は主君に忠義一途に仕えた。
He served his lord with single-minded loyalty.
忠義一途な家臣として知られていた。
He was known as a retainer of unwavering devotion.
Compound of 忠義 (loyalty) and 一途 (single-minded, wholehearted). The exact historical derivation is uncertain, but the combination straightforwardly conveys intense, undivided loyalty.