mé féiner

Etymology
From.

Noun

 * 1)  Someone who acts from self-interest, rather than the common good or the national interest.
 * 2) * 2015 June 29, Eoghan Plunkett, quoted in Ronan McGreevy "On 1916, and why Michael Collins 'was a pup'" The Irish Times:
 * As far as he was concerned, de Valera just fixed things for himself. He was a mé féiner.