You can voluntarily renounce (give up) your Irish citizenship. If you previously renounced your citizenship you can apply to reacquire it, but only if you were born on the island of Ireland.
Renounce Irish Citizenship
You can renounce your citizenship if:
You are 18 or over
You live outside the State
You must make a declaration of alienage to renounce Irish citizenship by completing Form 13.
Reacquire Irish Citizenship
You can apply to reacquire Irish citizenship (if you renounced it) if you were born on the island of Ireland.
If you gained citizenship based on descent from your parents, grandparents or great-grandparents or through naturalisation, you cannot apply to reacquire citizenship after you renounce it. You should submit a new application for citizenship by naturalisation or citizenship based on descent.
You must make a declaration of citizenship to reacquire Irish citizenship by completing Form 1.