This is the 6773rd most frequent Russian word.
ufs
It appears "ufs" is not a standard Russian word.
The word 'Уф' is used as an interjection expressing shock or disappointment.
Когда я услышал плохую новость, я только смог сказать: 'Уф!'
When I heard the bad news, I could only say: 'Uf!'
The word 'Уф' is used as an interjection expressing relief from effort.
После долгой пробежки он сел на скамейку и сказал: 'Уф, наконец-то!'
After a long run, he sat on the bench and said: 'Uf, finally!'
The word 'Уф' is used as an interjection expressing exasperation about the heat.