be a firm believer in (something)

be a firm believer in (something)

To have a strong conviction that something (stated after "in") is important or worthwhile. I'm a firm believer in resting on the weekends so that I don't get burned out.
See also: believer, firm
Farlex Dictionary of Idioms.

be a great/firm believer in something

believe strongly that something is good, important or valuable: My mother was a great believer in horoscopes all her life. The boss was a firm believer in developing strong teamwork.
See also: believer, firm, great, something
Farlex Partner Idioms Dictionary
See also:
  • be a great/firm believer in something
  • believer
  • be a great believer in (something)
  • true believer
  • lay (someone or something) alongside (someone or something)
  • lay alongside
  • sneeze at
  • sneeze at (someone or something).
  • sniff at
  • sniff at (someone or something).