What is shorten word meaning complementary?

There isn't a universally recognized shortened word meaning "complementary." However, depending on the context, you could use:

* Comp. (Especially in business or technical contexts)

* C. (Informal and brief, but might be ambiguous without context)

* Complem. (Slightly less formal than "comp.")

It's important to remember that using abbreviations can sometimes be unclear or confusing. If you're unsure about the context, it's always best to use the full word "complementary."