"Under" is a preposition that is commonly used to indicate something being positioned below or lower than something else. However, there are several synonyms that can be used in its place. Some examples include beneath, below, underneath, inferior to, subordinate to, and subject to. These synonyms can help provide variation and add uniqueness to your writing without altering the meaning of the sentence. For instance, instead of saying "The cat is under the table," you can opt for "The cat is beneath the table" or "The cat is below the table." Using synonyms not only enhances your writing but also makes it more enjoyable to read.