People use decreased activity (for example) where decrease in activity would be more literally correct. For example, reasons for my decreased activity usually refers to reasons for a decrease, not to ...
'A word in your shell-like' drops the noun from the original noun phrase. Are there any similar constructs?
I first encountered this from the mouth of 'Rumpole of the Bailey', and I've since seen it in lots of places. But I can't dredge up any similar constructions, where the original adjective remains ...