This is the 11619th most frequent Russian word.
жару
"Жару" means "heat" in English.
In this sentence, 'жару' refers to a weather condition where the temperature is high, indicating 'heat' in the environmental sense.
Я люблю играть в футбол в жару.
I love playing football in the heat.
Here, 'жару' is used to denote the heat source or temperature increase in an appliance like a smoker.
Он добавил жару в коптильню.
He added heat to the smoker.
In this playful expression, 'жару' refers to giving a good performance or showing energetic effort.