Assedly/Arsedly

However you spell it, arsedly, is a measure of effort. If you do something half-arsedly, for example, you will be doing at without putting much effort into things. But if you do things arsedly, then you putting maximum effort into it, or nearly so.

Similarly, one could say "I couldn't be arsed" if one is explaining how they weren't bothered to put effort into something.
(JB, TJ)