One word substitute is Anthropology.

Pathology: the science of the causes and effects of diseases, especially the branch of medicine that deals with the laboratory examination of samples of body tissue for diagnostic or forensic purposes.
Physiology: the branch of biology that deals with the normal functions of living organisms and their parts.
Philology: the branch of knowledge that deals with the structure, historical development, and relationships of a language or languages.
Anthropology: the study of human biological and physiological characteristics and their evolution.

One word substitute is Demography.

Geography: the study of the physical features of the earth and its atmosphere, and of human activity as it affects and is affected by these, including the distribution of populations and resources and political and economic activities.
Anthropology: the study of human societies and cultures and their development.
Topography: the arrangement of the natural and artificial physical features of an area.
Demography: the study of statistics such as births, deaths, income, or the incidence of disease, which illustrate the changing structure of human populations.

One word substitute is Sadist.

Anarchist: a person who believes in or tries to bring about anarchy.
Sophist: a paid teacher of philosophy and rhetoric in Greece in the Classical and Hellenistic periods, associated in popular thought with moral scepticism and specious reasoning.
Sadist: a person who derives pleasure, especially sexual gratification, from inflicting pain or humiliation on others.
Nihilist: a person who believes that life is meaningless and rejects all religious and moral principles.

One word substitute is Eccentric.

Lunatic: a person who is mentally ill (not in technical use).
Absurd: wildly unreasonable, illogical, or inappropriate.
Eccentric: (of a person or their behaviour) unconventional and slightly strange.
Maniacal: exhibiting extremely wild or violent behaviour.

One word substitute is Ascetic.

Monk: a member of a religious community of men typically living under vows of poverty, chastity, and obedience.
Ascetic: characterized by severe self-discipline and abstention from all forms of indulgence, typically for religious reasons.
Saint: a person acknowledged as holy or virtuous and regarded in Christian faith as being in heaven after death.
Spiritualist: a person who believes that the spirits of the dead can communicate with living people.