Bungled is the -ed form of bungle. In news English it often sits in front of a noun: a bungled robbery, a bungled rescue, a bungled attempt. That means people tried the thing and made a mess of it through clumsy or stupid mistakes. The word is a little sharp; it blames carelessness, not bad luck. You can also use it as a normal past: they bungled the job. Though actually, writers reach for bungled when the failure looks almost foolish from the outside — the plan was not just unsuccessful; it was badly handled.