Does anyone know where I might get my hands on a list of medical terms (diseases, etc.)? Diminutive forms are unnecessary. Crucially, the data cannot be dirty, and cannot contain words that are typically not used in a non-medical sense. The use of this list requires that false-positive identification of a medically relevant term be kept to a minimum. To this end it does not have to be exhaustive (precision vs recall).
I have found a number of lists on github. However ones like this have common first names included (such as Jacob, Jack, Marcus, Robin, etc.), meaning that all such terms would have to be manually weeded out before it could be used.
Health.gov data sets have diagnosis codes used by Medicare