There’s no need to waste time deliberating the best words to describe what you were supposedly doing when you sat at your desk reading websites like this all day. As Reddit user emhelldpp suggests, somebody has already figured that out. Simply copy the job description from your employer’s job listing when you get hired and save it for when you need it. Come resume updating time, all you have to do is paste the thorough, impressive-sounding job duties onto your resume—then make any necessary language tweaks.
Of course, you can also do this after you’ve put in your notice, or already left your job, since they’ll probably have put up a new listing for your replacement. Or you can go check your company’s job listings right now and see if you can find any similar positions.