Something that is made of both Imperial and Metric parts. These (usually old vehicles) can be difficult to work on, because to do the job properly at least 2 sets of the same tools are needed.
Gary: Can you pass me that weird spanner again?
Steve: The 13/16? Yeah ok...
Gary: Immetrical landrover crap
1. To describe someone that has a condition that causes them to be unable to understand SI units of measurement (colloquially referred as "Metric System").
This affliction has been historically endemic in regions of North America, Western Africa and Southeastern Asia.
When I told her I was 1.7 metres tall she stared at me in shock. Later I found out that sadly she's metrically handicapped.