Translation according to P. W. Joyce:
Conagher in several counties; Conadhchair, a place of firewood. The termination char added to conadh [conna], firewood : p. 12, I [reproduced below].
We have a great many ordinary Irish terminations, for the most part denoting the same as the English terminations ous and ly, namely "abounding in", "full of". The chief ordinary Irish terminations are ach, lach, nach, rach, trach, tach, seach, chair. For all these and others, see vol. ii. p. 3 [the part pertaining to char follows]. Char or chor. This postfix conveys a cumulative sense, which is well seen in Bennchor, a collection of peaks or gables, from beann, a peak (see Banagher, 1st Vol.). Exactly similar in formation to this, is Cranagher, in the parish of Clooney in Clare, which is anglicised from Crannchar, as Banagher from Bennchor, and signifies a place of cranns or trees. So also from grean [gran] gravel, we have granagher, a gravelly place, which forms again Gortnagranagher in Mayo and Limerick, the gravelly field (gort). There is a small river in the county Leitrim, flowing from Belhavel lake into the north-west corner of Lough Allen; it was formerly called the Duff, but it is now known by the equivalent name, Diffagher, which very well represents the sound of Duibheachair (ea, vowel sound, inserted), black river, from dubh, black. The celebrated plague called the yellow sickness, which swept over the British Islands and the Continent in the seventh century, is sometimes called buidheachair in the Irish annals. This word is reproduced in the name of Cloonboygher near Carrigallen in Leitrim; but here it is probable that the term was applied to the yellow colour of the water or of the mud; and that the name means the meadow of the yellowish water (buidhe, yellow).