What is the opposite of sentence?

There isn't a single perfect opposite for "sentence" in the way that "hot" is the opposite of "cold." It depends on how you're thinking about the word. Here are a few possibilities:

If you're thinking about the grammatical structure:

* Phrase: A group of words that does not have a subject and verb combination. Examples: "on the table," "very quickly."

* Clause: A group of words with a subject and verb, but it might not be a complete thought. Examples: "When I went to the store."

* Word: A single unit of meaning.

If you're thinking about the legal concept of a sentence:

* Acquittal: A legal decision that someone is not guilty.

* Pardon: A legal forgiveness for a crime.

* Commutation: A reduction of a sentence.

If you're thinking about the act of putting words together:

* Silence: The absence of sound, especially speech.

* Noise: Unintelligible sound.

It really depends on the context!