Article in Ireland abridged: any one of two? (6)
I believe the answer is:
either
'any one of two?' is the definition.
(one of two options)
'article in ireland abridged' is the wordplay.
'article' becomes 'the' (the definite article).
'in' indicates putting letters inside.
'ireland' becomes 'eire' (poetic name for Ireland).
'abridged' means to remove the last letter.
'eire' with its last letter taken away is 'eir'.
'the' inserted within 'eir' is 'EITHER'.
(Other definitions for either that I've seen before include "could be one of two" , "Choice of two" , "Her tie (anag.)" , "offered a choice" , "No matter which (of two)" .)