One Word Substitution

A person who walks in their sleep is a somnambulist. Somna = sleep, ambulate = walk. Hence, a somnambulist is a person who walks in their sleep.

Ans-4

Celibacy is the state of being unmarried, often associated with religious vows, though it generally refers to the state of not being married.

A glutton is a person who eats and drinks excessively.

A sexton is an officer of a church who is in charge of the maintenance of the church buildings and grounds.

A pessimist is someone who tends to see the worst aspect of things or believes that the worst will happen.

An ambidexter (or ambidextrous person) is someone who can use both hands with equal ease.

An inferno is a large fire that is dangerously out of control, often used metaphorically to describe a place like hell.

A sphinx is a mythical creature from ancient Egyptian mythology, typically depicted with the body of a lion and the head of a human. The other options refer to unrelated terms like a speech (spiel), a drink (tequila), or a spirit (sylph).

A physiotherapist is a healthcare professional who specializes in the treatment of physical injuries, muscle problems, and mobility issues. Psychologists deal with mental health, while massagers focus on relaxation rather than medical rehabilitation.

Shunting is the railway term for moving railway carriages or locomotives from one track to another, often to assemble or disassemble trains. Milling, treading, and wrapping are unrelated to railway operations.

A decagon is a polygon with ten sides. The prefix 'deca-' refers to the number ten, while the suffix '-gon' refers to angles or sides.

A teetotaler is a person who practices total abstinence from alcoholic beverages. The other terms are unrelated to alcohol consumption.

Trespassers are individuals who enter land or property without the owner's legal permission. The other options do not specifically describe unauthorized entry.

An archaeologist is a person who studies human history and prehistory through the excavation of sites and the analysis of artifacts. Anthropologists study human societies more broadly, while paleontologists focus on fossils.

Graphology is the study of handwriting to infer a person's character or personality traits. Cartography is map-making, and lithography is a printing process.

Gerontology is the scientific study of old age, the process of aging, and the problems faced by the elderly. Genetics is the study of heredity, and genealogy is the study of family history.

A lexicographer is a person who compiles, writes, or edits dictionaries. The other options refer to different trades like undertakers or tinkerers.

To postpone means to delay or put off an event until a later time. Prepone is the opposite, meaning to move an event to an earlier time.

Demography is the statistical study of human populations, including size, structure, and distribution. Topography is the study of land surfaces, and cartography is map-making.

A fanatic is a person who is filled with excessive and often uncritical zeal or enthusiasm for a cause or activity. A fan is an enthusiast, but 'fanatic' implies an extreme level.