Murks
Work done improperly, with faults, badly. Duden’s definition.
Pfusch
Work done carelessly and untidily.
Schnellschuss
Quick shot. Something produced at short notice, without longer planning and without thorough preparation.
nachbessern
To improve afterwards. Duden’s example is einen Gesetzentwurf nachbessern, to rework a draft law.
Montagsauto
Monday car. A car that has relatively many defects from the start, as if it had been built on a Monday.
Bananensoftware
Banana software. Software delivered unripe, which ripens at the customer. The idea behind it is called the Bananenprinzip, the banana principle.