Aculeous is a word that describes anything that has thorns, spines, or prickles. This includes plants, animals, and even certain rocks. Some synonyms that can be used instead of aculeous are spiny, prickly, thorny, bristly, barbed, heathery, and jagged. These words are often used to describe cacti, rose bushes, porcupines, and other things that have sharp projections. Additionally, aculeous can also be replaced by words like spiky, pointed, and needle-like, which can describe things like icicles, stalagmites, or even spikes in sports gear. Overall, there are many words that can be used to describe things that are aculeous, depending on the specific context.