be on firm ground

be on firm ground

To be certain of or comfortable with something. Anna can tutor you—she's on firm ground with diagramming sentences.

See also: firm, ground, on

be on firm ground

be sure of your facts or secure in your position, especially in a discussion.

See also: firm, ground, on

be on firm ˈground

be sure about your beliefs, knowledge, etc.; be confident: I don’t know a lot about physics, I’m afraid. I’m on firmer ground with mathematics, which I studied at university.

See also: firm, ground, on