doctorer

Etymology tree
Proto-Indo-European *deḱ-der.
Proto-Italic *dokeō
Latin doceō
Proto-Indo-European *-tōr
Proto-Italic *-tōr
Latin -tor
Latin doctorbor.
Old French doctur
Anglo-Norman doctourder.
Middle English doctour
English doctor
Proto-Indo-European *-yósder.
Proto-Italic *-āzijos
Latin -āriusnom.
Latin -āriusbor.
Proto-Germanic *-ārijaz
Proto-West Germanic *-ārī
Old English -ere
Middle English -ere
English -er
English doctorer
From doctor + -er.