The word 'dunnigan' is a surname that is pronounced as /ˈdʌnɪɡən/. It can be divided into two parts, 'dun' and 'nigan'. The first part, 'dun', is pronounced as /dʌn/ and means dark or dull in color. The second part, 'nigan', is pronounced as /ˈnɪɡən/ and has unclear origins, but is common in Irish surnames. Combining these two parts, the spelling 'dunnigan' is derived, and represents the phonetic pronunciation of the surname.