Definition:
The word "completing" is the present participle form of the verb "complete." It refers to the action of making something whole or finished. When you are completing something, you are putting the final touches on it or bringing it to an end.
Complete (verb): To finish something.
Completion (noun): The state of being finished.
Completeness (noun): The state of being complete or whole.
"Complete the circle": This idiom means to return to a starting point or to finish something that has been left unfinished.
Phrasal Verb: "Wrap up": This means to finish something.
"Completing" is a versatile word that primarily means to finish something, but it can also describe things that help finalize a whole.