Stretching out is a phrase that means to extend something to its full length or width. Some synonyms for this word include elongating, expanding, lengthening, and spreading. Each of these words emphasizes the act of increasing the size or space of something. Another synonym for stretching out could be dilating, which specifically means to expand in all directions. Additionally, the word protruding can be used as a synonym for stretching out when focusing on a particular part of the body that extends beyond its usual or expected position. Overall, there are many different words that can be used to express the idea of stretching out, depending on the context and intended meaning.