kaitoa
1. (interjection) it serves (you) right! - expresses satisfaction or complacency at some event or misfortune befalling someone else.
(Te Pihinga Textbook (Ed. 2): 107; Te Pihinga Audio Tapes/CDs (Ed. 2): exercise 40; Te Kōhure Textbook (Ed. 2): 163;)
Kua panaia a Hāmi i tana mahi. Kaitoa! Koia nā te hua o te māngere. / Sam has been sacked from his job. Serves him right! That's what you get for being lazy.
See also e nge