1. EFFICACIOUS 
Ans: Effective

2. SUBSEQUENT
Ans: Consecutive

3. TRANQUIL
Ans: Calm

4. CONDEMN
Ans: Denounce

5. ENGULF
Ans: Inundate

6. REDUNDANT
Ans: Unnecessary

7. SCANTY
Ans: Meagre

8. COMPLACENT
Ans: Self-satisfied

9. DISCERN
Ans: Perceive

10. INIMICAL
Ans: Hostile

11. VENERABLE
Ans: Respectable

12. INCESSANT
Ans: Persistent

13. SANCTION
Ans: Approval

14. JEOPARDY
Ans: Danger

15. IGNOMINY
Ans: Shame, disgrace

16. ALOOF
Ans: Separated

17. EXASPERATE
Ans: Infuriate, make angry

18. FEIGN
Ans: Pretend

19. BEGUILE
Ans: Deceive

20. DEFERENCE
Ans: Honor, respect