たまったもんじゃない

Also written 堪ったもんじゃない

Meanings

1. Expression, い-adjective intolerable; unbearable; unendurable (emphatic form of たまらない) See also: たまらない.
2. tremendous; out of this world; irresistible See also: たまらない.
3. cannot help (doing); cannot but do; anxious to do See also: たまらない.

Jinuma: Japanese Dictionary · Word lists