the current definition says:
Copywriting is the act or occupation of writing text for the purpose of advertising or other forms of marketing.
that sounds stupid. a more cool-sounding usage of the word would be something along the lines of literally writing down a copy of something.
example: i see some nice dialogue in a game, i need it in a text-written form so i can reference it better. i go ahead and write a copy of this dialogue in a text editor. that sounds like a nice definition for the word "copywriting".
i should probably start using it more, but other people might not catch up with that.