The term 'ONE'S LOINS' can be summarized by the crossword solution 'GIRD', which is a four-letter word. Girding ONE's loins is an idiom that means to prepare oneself for a difficult task or situation. It originates from the Bible, where it was used to describe the act of putting on a belt or girdle in preparation for battle. In modern usage, it is often used to express determination and readiness for a challenge.