Synonyms for “Solid”:

1. Firm
2. Stable
3. Hard
4. Durable
5. Substantial
6. Strong
7. Resilient
8. Massive
9. Tough
10. Stiff
11. Stalwart
12. Unyielding
13. Solidified
14. Compacted
15. Unbreakable
16. Unmovable
17. Immovable
18. Unshakable
19. Permanent
20. Constant
21. Enduring
22. Consistent
23. Inalterable
24. Dependable
25. Trustworthy
26. Secure
27. Inflexible
28. Stony
29. Tenacious
30. Unflinching

When searching for a word to express something that is strong and reliable, the best ideas are to look for a synonym for the word “solid”. There are many other words for solid, such as firm, stable, hard, durable, substantial, strong, resilient, massive, tough, stiff, stalwart, unyielding, solidified, compacted, unbreakable, unmovable, immovable, unshakable, permanent, constant, enduring, consistent, inalterable, dependable, trustworthy, secure, inflexible, stony, tenacious, and unflinching. All of these words can be used to express something that is strong and reliable, and can be used in place of the word “solid”.