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
Farlex Dictionary of Idioms.

be on firm ground

be sure of your facts or secure in your position, especially in a discussion.
See also: firm, ground, on
Farlex Partner Idioms Dictionary

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
Farlex Partner Idioms Dictionary
See also:
  • firm hand on the tiller
  • tiller
  • have a firm grip on (someone or something)
  • keep a firm grip on
  • keep a firm grip on (someone or something)
  • question of
  • it's a question of (something)
  • it's a question of something
  • have a handle on (something)
  • get a handle on (something)