1. Inadequate
2. Incompetent
3. Ineffectual
4. Unproductive
5. Unfit
6. Unsound
7. Unserviceable
8. Unsuitable
9. Useless
10. Impotent
11. Inoperative
12. Unfit
13. Unavailing
14. Unprofitable
15. Unsuited
16. Unqualified
17. Unsatisfactory
18. Unhelpful
19. Unfit
20. Inapt
21. Inexpedient
22. Unfit
23. Unfit
24. Unsuited
25. Unfit
26. Unqualified
27. Ineffectual
28. Unfit
29. Unproductive
30. Unfit

When trying to find the best synonyms for the word «inefficient», there are a variety of options to choose from. Whether you are looking for other words for «inefficient», a synonym for «inefficient», or the best ideas for synonyms, there are many options available. Some of the most common synonyms for «inefficient» include inadequate, incompetent, ineffectual, unproductive, unfit, unsound, unserviceable, unsuitable, useless, impotent, inoperative, unavailing, unprofitable, unsuited, unqualified, unsatisfactory, unhelpful, inapt, and inexpedient. Each of these words has its own unique meaning and can be used to accurately describe a situation or object that is not efficient.