The phrase "give grounds for" implies providing a reason, justification, or evidence for a particular claim. Synonyms of this phrase include "offer support for," "provide a basis for," "justify," "substantiate," "validate," "warrant," and "give rise to." These synonyms can be used interchangeably, depending on the context and tone of the statement. For instance, if someone wants to support their argument, they can use any of these synonyms to show that their opinion is rooted in evidence and logical reasoning. Similarly, if someone wants to establish the truth of a statement, they can use these synonyms to demonstrate that it is valid and well-founded.