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

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