Mottainai
Etymology
From Japanese (もったいない), with roots in Buddhist thought; it combines a sense of the intrinsic worth or dignity of things (“mottai”) with negation (“nai”). Grammatically it is an adjective, often used as an exclamation of regret over waste. It was carried onto the world stage by the Kenyan environmentalist Wangari Maathai, who adopted it as a rallying word for reduce, reuse, recycle, and respect.
adjective · /moht-tie-NIGH/
Expressing regret at wastefulness — a sense that something useful is being thrown away or not honored.
What it names
The pang of “what a waste” at seeing anything of value squandered, and the accompanying pull to use things fully and respectfully.
Example
Throwing out those vegetable peels feels mottainai — I keep meaning to make stock instead.
Related idea
English wasteful judges behavior as an adjective of blame; mottainai is more an exclamation of regret and reverence, carrying a quiet respect for the thing being wasted.