Used to indicate that something is excessive or unreasonable no matter how you look at it; 'even so' or 'really too (much)'.
いくらなんでもこの値段は高すぎるよ。
Even so, this price is too high.
彼が遅刻したのは仕方ないが、いくらなんでも三時間は長すぎる。
It's understandable he was late, but three hours is really too long.
いくらなんでもそれを一人でやらせるのは無責任だ。
No matter how you look at it, making him do that alone is irresponsible.