One Word Substitution: Complete Guide for SSC, Banking & Other Exams

One Word Substitution (OWS) means replacing a descriptive phrase with a single precise word. This topic appears in virtually every competitive exam — SSC CGL, CHSL, MTS, Constable GD, Banking, Railways, and UPSC. It tests your vocabulary depth and precision.

Key Categories You Must Know

  • Phobia Words: Hydrophobia (water), Claustrophobia (confined spaces), Acrophobia (heights), Agoraphobia (open spaces)
  • -cide Words (killing): Homicide (human), Fratricide (brother), Matricide (mother), Patricide (father), Regicide (king)
  • -logy Words (study of): Ornithology (birds), Entomology (insects), Cosmology (universe), Seismology (earthquakes)
  • Specialists: Paediatrician (children), Dermatologist (skin), Cardiologist (heart), Ophthalmologist (eyes)
  • Places: Apiary (bees), Aviary (birds), Aquarium (fish), Sanctuary (animals in wild)

Memory Tricks

Root Word Method: Learn Latin and Greek roots — they unlock hundreds of words.
bene = good (benevolent, benefactor) | mal = bad (malevolent, malice) | philo = love (philosophy, bibliophile)

High-Frequency OWS in Exams

PhraseOne Word
One who walks in sleepSomnambulist
Fear of waterHydrophobia
Study of birdsOrnithology
Killing of a kingRegicide
Place where bees are keptApiary

Practice MCQs: One Word Substitution for Constable GD 2026

Test your understanding with these 10 MCQs on One Word Substitution. These are designed to reinforce the concept explained above.

Q1. One who can speak two languages:

(A) Trilingual   (B) Bilingual   (C) Multilingual   (D) Monolingual

Answer: (B) Bilingual

Explanation: 'Bilingual' refers to a person who speaks two languages with equal proficiency.

Q2. The study of the past:

(A) Geography   (B) History   (C) Archaeology   (D) Anthropology

Answer: (C) Archaeology

Explanation: 'Archaeology' is the study of human history and prehistory through the excavation of sites and analysis of artifacts.

Q3. A place where fish are kept:

(A) Apiary   (B) Aviary   (C) Aquarium   (D) Vivarium

Answer: (C) Aquarium

Explanation: An 'aquarium' is a transparent tank of water in which fish and other water creatures are kept.

Q4. One who does not believe in God:

(A) Agnostic   (B) Theist   (C) Atheist   (D) Deist

Answer: (C) Atheist

Explanation: An 'atheist' is a person who disbelieves or lacks belief in the existence of God or gods.

Q5. The killing of oneself:

(A) Homicide   (B) Regicide   (C) Suicide   (D) Fratricide

Answer: (C) Suicide

Explanation: 'Suicide' is the act of intentionally causing one's own death.

Q6. A person who loves books:

(A) Bibliophile   (B) Bibliophobe   (C) Polymath   (D) Pedant

Answer: (A) Bibliophile

Explanation: A 'bibliophile' is a person who collects or has a great love of books. From Greek: biblion (book) + philos (loving).

Q7. One who lives in a foreign country:

(A) Nomad   (B) Immigrant   (C) Expatriate   (D) Refugee

Answer: (C) Expatriate

Explanation: An 'expatriate' is a person who lives outside their native country, especially temporarily.

Q8. That which cannot be seen:

(A) Transparent   (B) Invisible   (C) Opaque   (D) Translucent

Answer: (B) Invisible

Explanation: 'Invisible' means unable to be seen; not visible to the eye.

Q9. A person who looks at the bright side of life:

(A) Pessimist   (B) Realist   (C) Optimist   (D) Fatalist

Answer: (C) Optimist

Explanation: An 'optimist' is a person who tends to be hopeful and confident about the future or the success of something.

Q10. The study of birds:

(A) Entomology   (B) Ornithology   (C) Zoology   (D) Ecology

Answer: (B) Ornithology

Explanation: 'Ornithology' is the scientific study of birds. From Greek: ornis (bird) + logos (study).