This is the 180th most frequent Serbian word.
топло
Warm.
The word 'топла' is used here as an adjective to describe the temperature of the water, indicating its warm quality.
Вода је топла и пријатна за купање.
The water is warm and pleasant for swimming.
The word 'топлу' here figuratively describes the quality of the word as being kind and heartfelt.
Он ми је упутио топлу реч за подршку.
He gave me a warm word of support.
The word 'топла' is used literally to describe a cozy, warm environment of the cave.