At
http://www.20000-names.com/male_irish_names_02.htm, they give a list of Irish names, and the ones beginning with D are as follows -
DACEY: "Tenant, vassal." Irish surname transferred to unisex forename use, itself originally a nickname for a feudal servant, a member of the Déise, a word which ultimately traces back to Indo-European *dem-s, meaning "house."
DÁIBHÍDH: Irish/Gaelic form of David, meaning "beloved."
DAIRE (Dáire): Irish name derived from the Gaelic element dáire, meaning "fertile, fruitful."
DAITHI (Daithí): Irish/Gaelic name meaning "swift."
DALEY: "Assembly, gathering." Irish surname transferred to forename use, itself from the Gaelic surname Ó Dálaigh, meaning "descendant of Dálach."
DALY: Variant of Irish Daley, meaning "assembly, gathering."
DARA: "Oak." Abbreviated form of Irish/Gaelic Mac Dara ("son of oak") a forename common in Ireland today, especially in Connemara.
DARACH: Variant of Irish Dara, meaning "oak."
DAVIN: "Little black one." Irish surname transferred to forename use, itself from Gaelic Ó Duibhín "descendant of Duibhín."
DEAGLAN (Deaglán): "Fully good." Irish/Gaelic name composed of the elements deagh "good" and lán "full."
DEASUN (Deasún): Variant of Irish Desmond, meaning "from Munster."
DELANEY: "Dark challenger." Irish surname transferred to unisex forename use, itself from Gaelic Ó Dubhshláine "descendant of Dubhshláine."
DESMOND: From the Irish nickname for someone "from Munster."
DEVIN: Irish surname transferred to English forename use, itself from Gaelic Ó Damháin, "descendant of Damhán," a byname meaning "fawn."
DIARMAID: Irish myth name of a High King of Ireland, meaning "freeman; without envy."
DIARMUID: Variant of Irish Diarmaid, meaning "freeman; without envy."
DONAGH: Irish form of Gaelic Donnchadh, meaning "brown warrior."
DONAL: Irish nickname for Gaelic Domhnall, meaning "world ruler."
DONOGH: Variant of Irish Donagh, meaning "brown warrior."
DONOUGH: Variant of Irish Donagh, meaning "brown warrior."
DONOVAN: "Little dark/black one." Irish surname transferred to forename use, itself from Gaelic Ó Donndubháin, meaning "descendant of Donndubhán."
DORAN: "Exile, wanderer." Irish surname transferred to forename use, itself from Gaelic Ó Deoradháin, meaning "descendant of Deoradhán."
DOYLE: Irish form of Scottish Dougal and Dugald, meaning "dark stranger."
DRISCOLL: "Messenger." Irish surname transferred to forename use, from Gaelic Ó h-Eidirsceóil "descendant of the messenger," from the word eidirsceól "go-between, intermediary, news bearer," itself composed of the elements eidir "between" and scéal "story, news."
DRISKOLL: Variant of Irish Driscoll, meaning "messenger."
DUANE: English/Irish form of Gaelic Dubhán, originally a byname which was the diminutive of Gaelic dubh, meaning "dark, black."
DWAYNE: Variant of English/Irish Duane, meaning "dark, black."
Stephen
