A hypochondriac is one who obsesses over perceived health conditions to an abnormal extent. We get this word from French hypocondriaque, which traces to Greek hypokhondria, meaning "under the cartilage". What gives? Well, whenever Ancient Greek doctors encountered a medical condition they couldn't explain, they blamed it on soft tissues and organs, which can often be found under a person's cartilage. Throughout the years, people anxious about their health fretted about having failing organs, and thus the word got applied to those people. Breaking down hypokhondria, we can see the words hypo, meaning "below", and khondros, meaning "cartilage". Hypo is reconstructed as deriving from the Proto-Indo-European root upo, meaning "under", and khondros has a bit more obscure of an origin, but some etymologists reconstruct it to PIE ghrendh, meaning "crushing". This, however, is unconfirmed. Usages of hypochondria and hypochondriac have been very closely paralleling each other throughout the centuries, and both are now in moderate decline.
Adam Aleksic, a leading contender for valedictorian of his high school, is a 214-month-old boy with disturbing interests in etymology, vexillology, geography, and law. Adam would like to one day visit Tajikistan and probably isn't spying for the Uzbek government.
The Etymology Nerd