MonahanIrish From Irish Ó Manacháin meaning "descendant of Manacháin". The given name Manacháin meant "little monk", from manach "monk" and a diminutive suffix.
MoriartyIrish From Irish Ó Muircheartach meaning "descendant of Muirchertach". This was the surname given by Arthur Conan Doyle to a master criminal in the Sherlock Holmes series.
NixonEnglish Means "son of Nick". A famous bearer was the American president Richard Nixon (1913-1994).
NoelFrench, English Either from the given name Noël, or else derived directly from Old French noel "Christmas" and given to a person who had a particular connection with the holiday.
NolanIrish Anglicized form of Irish Ó Nualláin meaning "descendant of Nuallán".
ObamaLuo From a rare Luo given name meaning "crooked, bent". It was possibly originally given to a baby who had an arm or leg that looked slightly bent immediately after birth or who was born in the breech position.
Ó CnáimhínIrish Means "descendant of Cnámh", Cnámh being a nickname meaning "bone".
Ó CochláinIrish Means "descendant of Cochlán", where the given name Cochlán is derived from Irish cochal "cape" or "hood". This surname originated in County Cork, Ireland.
O'HaraIrish From the Irish Ó hEaghra, which means "descendant of Eaghra", Eaghra being a given name of uncertain origin. Supposedly, the founder of the clan was Eaghra, a 10th-century lord of Luighne. A famous fictional bearer of this surname is Scarlett O'Hara, a character in Margaret Mitchell's Gone With The Wind (1936).