(Wait until submissions are open to submit. We are not an advice blog, but our sister blog is [artist-advice.tumblr.com]. PLEASE READ THE FAQ BEFORE ASKING QUESTIONS. The admins at artist-problems would like to believe that you are capable of clicking and reading those links on your own. To see previously used problems, please refer to the FAQ. Thank you!)
Hiatus is a break for an undetermined amount of time. In short, if someone says they’re going on hiatus it means they’re going to not be uploading art for a while.
RP is Roleplay, which is when people assume and act/type out plotlines as fictional characters (sometimes their own). I think that’s a poor definition, since it’s a really broad subject. It would take a long time for me to properly define, so feel free to explore it yourself.
CG I believe is a graphics term and it’s a type of shading that’s pixel based.
I hope this is all correct and that it helps!