Definition of irrelevancy in US English:

irrelevancy

noun

  • See irrelevance

    • ‘The question is, will the United Nations follow the League of Nations and risk irrelevancy.’
    • ‘When everything is digital, the word digital becomes an irrelevancy.’
    • ‘Any delineation between the nominally public and non-public spheres is now a hair-splitting irrelevancy.’
    • ‘In other words, it will be phased out, perhaps not entirely, but close enough as to make it an irrelevancy.’
    • ‘But it's wild generalizations like this that point up the irrelevancy of such commercially-driven lists.’

Pronunciation

irrelevancy

/i(r)ˈreləv(ə)nsē//ɪ(r)ˈrɛləv(ə)nsi/