остыва́ть

uncommon #9703verbimperfective perfective is осты́ть

1.
to cool down, to become cold, to get cold
Ешь скоре́е, суп остыва́ет.
Eat quickly, the soup is getting cold.
2.
to calm down, to cool off, to lose interestfigurative
Он легко́ выходит из себя́, но бы́стро остыва́ет.
He loses his temper easily but calms down quickly.
Of anger, passion or enthusiasm.

Examples

Том, еда́ остыва́ет.
Tom, your food's getting cold.
Отжигаемая деталь остывала на воздухе.
The part being annealed was cooling in the air.
Твой ко́фе остыва́ет.
Your coffee is getting cold.
Ужин остыва́ет.
Supper's getting cold.
Напекаемые для гостей пироги остывают на столе.
The pies being baked for the guests are cooling on the table.
Плохо протапливаемый дом зимой быстро остывает.
The poorly heated house cools down quickly in winter.
Металл, расхолаживаемый водой, быстро остывал.
The metal, cooled by water, cooled down quickly.
Ковыряемая ложкой каша быстро остывала.
The porridge being poked with a spoon quickly cooled down.

Imperative
ты	остыва́й
вы	остыва́йте

Active present	остыва́ющий	cooling, cooling down, getting cold
Active past	остыва́вший	cooling, getting cold, that was cooling, that was getting cold
Passive present	-
Passive past	-
Gerund present	остыва́я	while doing (present)
Gerund past	остывав остывавши	while doing (past)