"Matěj and František are good fathers."
Translation:Matěj a František jsou dobří otcové.
November 25, 2017
The pattern muž has two possible endings in nominative plural. Some nouns can use both (with one of them preferred), some use only the "-i" ending and some (like "otec") use only "-ové" ending.
In this case "otci" would be colloquial, non-standard.