Position:
* Beneath: This is a very close synonym, often interchangeable with "under."
* Below: Similar to "beneath," but often used to describe vertical position.
* Sub: A more formal synonym, often used in scientific or technical contexts.
* Over: This is the opposite of "under," but it can sometimes be used as a synonym when referring to something covering something else. For example, "The blanket was under the bed" could be rewritten as "The blanket was over the bed."
Other meanings:
* Less than: When "under" is used to describe a quantity. For example, "The cost was under $10."
* Subject to: When "under" refers to being controlled or governed by something. For example, "The company is under new management."
Informal:
* Down: This is a more informal synonym, often used in casual conversation.
* On: This can be used in place of "under" when referring to something being supported by something else, but it's not always a direct synonym.
To choose the best synonym, consider the specific meaning of "under" in your sentence and the desired tone.