One word substitution is a word used to describe the phrase with a single word that expresses the same meaning. It is often used in writing and language instruction as a way to improve concision and clarity.

It is a technique where a single word is used to replace a phrase or sentence that has a similar meaning. This can be done to make writing or speech more concise and efficient. 

For Example, using the word “feline” instead of “cat-like,” or “vegetarian” instead of “someone who does not eat meat.” This technique can also be used to replace technical or complex terms with simpler, more commonly understood words.

Here you will get one word substitution starting with O.