The phrase "solid grounds" refers to a strong foundation or a firm basis for something. Synonyms for this phrase include solid foundation, strong footing, sturdy support, firm bedrock, reliable basis, dependable groundwork, stable platform, secure groundwork, robust infrastructure and unshakable footing. These synonyms emphasize the importance of a solid foundation in ensuring the success and stability of anything, whether it's a building, a relationship or even an idea. Having solid grounds provides a sense of security and confidence in knowing that something is built on a strong and dependable base.