The term 'Fiber-Yielding Shrub' refers to a type of plant that produces fibers which can be used for various purposes. One example of such a plant is Aloe, which is a four-letter word that fits the crossword solution. Aloe is a succulent plant species that is native to Africa and is widely cultivated for its medicinal properties. It is also known for its fiber-yielding qualities, which are used in the production of textiles, paper, and other materials.