What's the title for those who study names?

Etymology is the study of the history of Words, their origins, & how their form and meanings have changed over time.

Onomastics is the scientific study of place-names, personal names, and proper names of all kinds. Toponymy, the study of place names, & Anthroponomastics, the study of personal names of human beings including subdivisions such as Surnames & Nicknames, are some of the principal branches of onomastics.

The International Council of Onomastic Sciences is an international academic organization of scholars with a special interest in onomastics.