This is the 13th most frequent Russian word.
но
"But."
Here 'но' serves to contrast two characteristics of the described noun, highlighting a positive aspect despite a potential drawback.
Это дорого, но качественно.
It is expensive, but of good quality.
In this example, 'но' indicates a limitation or a condition that accompanies the agreement, introducing a nuance or detail to the statement.
Он согласен, но с некоторыми условиями.
He agrees, but with some conditions.
In this sentence, 'но' is used as a conjunction to introduce a contrasting fact or situation that prevents the fulfillment of the first clause.