Translation according to P. W. Joyce:
Killamanagh in Galway; Cill-a-manach, church of the monks. The a after kill is the inserted vowel sound: p. 7, VII [reproduced below]. See Kilnamanagh, vol. i.p. 492 [reproduced below].
VII. There are certain consonants which, when they come together, cannot well be pronounced by the Irish people (especially those accustomed to Irish), without the insertion of a short vowel sound between them - which acts as it were like a buffer - which acts as it were like a buffer - so as to add a syllable to the word; for example, errub for herb, Char-less for Charles, ferrum for firm (see this set forth in my "English as we speak it in Ireland", p. 96). Place-name example: Cloncallick, in Fermanagh and Monaghan, Cloon-cailc, meadow of lime or chalk. Calc would be pronounced calc (one syll.) by an Englishman, but callick by an Irishman, as it is here.
I have already conjectured (p. 314) that about a fifth of the kils and kills that begin names are woods; the following are a few examples: - Kilnamanagh, a barony in Tipperary, the ancient patrimony of the O'Dwyers, is called by the Four Masters, Coill-na-manach, the wood of the monks.