Question

which is the act of copying other's work and showing it as one's own word?

Answer 1

I think the word you are looking for is Plagiarism.

From Wikipedia:

Plagiarism is the "wrongful appropriation" and "stealing and publication" of another author's "language, thoughts, ideas, or expressions" and the representation of them as one's own original work.

Answer 2

Answer:

Plagiarism.

Plagiarism is taking other people's work/ideas and pretending it's your own. If you see someone's work/idea that you like and you want to copy it, write/put it in your own words. This way, it won't be called plagiarism/copying someone else's work/ideas.