A one-word substitute is simply a word which can replace a full sentence with a single word. This topic is very important from the competitive exam point of view and forms a significant part of the verbal ability section as 3 to 5 questions are asked from this topic.
| S. No. | Description | Word |
| 1. | A person who believes in or tries to bring about a state of lawlessness | Anarchist |
| 2. | A person who has changed his faith | Apostate |
| 3. | A person blindly devoted to an idea | Chauvinist |
| 4. | One who is recovering health after illness | Convalescent |
| 5. | A person having a sophisticated charm | Debonair |
| 6. | One who runs away from justice | Fugitive |
| 7. | One who believes in fate | Fatalist |
| 8. | A person who acts against religion | Heretic |
| 9. | A person who likes or admires women | Philogynist |
| 10. | A person who speaks more than one language | Polyglot |
| 11. | One who lives in solitude | Recluse |
| 12. | A large number of fishes swimming together | Shoal |
| 13. | A large group of people | Horde |
| 14. | A funeral procession | Cortege |
| 15. | The medieval forerunner of chemistry | Alchemy |
| 16. | A keeper or custodian of a museum | Curator |
| 17. | The theory or philosophy of law | Jurisprudence |
| 18. | A building where animals are butchered | Abattoir |
| 19. | A room in a public building where outdoor clothes or luggage may be left | Cloakroom |
| 20. | A place where wild animals live (often hidden and underground) | Lair |