Mottainai

Another basic vocabulary.
This word suddenly became common worldwide, thanks to Dr. Wangari Maathai, a Nobel Peace Laureate from Kenya.

It is a Japanese concept meaning "it is a pity to waste".
hmm, difficult to translate its subtle meanings...
It's not accusing, but rather a word that comes out with a sigh. We use it when we don't want to throw away something, or when we think that a thing or person is not treated properly.

Examples
"It is mottainai to throw out leftovers. Eat it all!"
"How mottainai, we can still use this clothes"