Delete article in Irish Gaelic (5)
I believe the answer is:
erase
'delete' is the definition.
(erasing is a kind of deleting)
'article in irish gaelic' is the wordplay.
'article' becomes 'a' (indefinite article).
'in' means one lot of letters goes inside another.
'irish gaelic' becomes 'erse' (I've seen this before).
'a' inserted within 'erse' is 'ERASE'.
(Other definitions for erase that I've seen before include "Remove permanently" , "Blot out" , "Efface" , "Remove from memory" , "Scratch" .)