Rare, archaic term for a traditional Japanese loincloth (fundoshi). In modern Japanese, ふんどし is the standard word.
In old documents, the word 緊褌 is used to mean a loincloth.
gird oneself up; brace oneself; prepare for a challenge
The exact derivation is uncertain. The kanji 緊 (tighten) and 褌 (loincloth) combine to suggest a tightly fastened loincloth, but the word is not in common use.