A contraption is a device that has a specific purpose and is often overly complicated. If your dad yells, “Get that contraption out of here!” He doesn’t appreciate the Rube Goldberg machine you made out of his golf clubs.
The word is English, all right, but how it got here is a mystery. It may be from a combination of contrive and adaptation. Contraptions — also called gadgets or gizmos — are devices people make for various purposes. Often, this word is used when someone isn't quite sure what something is, as in "What's that contraption?" Oh that’s just a dog-walking machine made of a roller skate, bacon, and four paper clips.