monomath
A person with an extensive knowledge of a single subject or field, but little knowledge of others.
It is not a refuge for self-indulgent monomaths to channelize their aggressions within a community of colleagues and students.
Where it comes from
From mono- (“one, single”) + Ancient Greek μάθη (máthē, “learning”), from μανθάνω (manthánō, “to learn”). Compare polymath.
Adapted from the Wiktionary entry monomath (CC BY-SA 4.0).