The correct spelling of the word "brightman" is usually pronounced as /ˈbraɪtmən/. In this pronunciation, "b" is pronounced with a strong "br" sound, "r" is pronounced firmly, "i" with a long "i" sound, "g" with a soft "g" sound, "h" is silent, "t" with a soft "t" sound, "m" and "a" are pronounced with their usual sound. Overall, the spelling of "brightman" is quite straightforward for native English speakers.
There is no dictionary definition for the word "brightman".