This is the 11251st most frequent Polish word.
gęstą
"Thick" or "dense" (feminine singular accusative form).
Here, 'gęstą' is used as an adjective describing the consistency of the soup, indicating that it is thick.
Lubię tę gęstą zupę pomidorową.
I like this thick tomato soup.
In this sentence, 'gęstą' describes the fog, signifying its density and limited visibility.
Czasami lepiej przejść przez gęstą mgłę powoli.
Sometimes it's better to move through the dense fog slowly.
Here, 'gęstą' characterizes the atmosphere, referring to the abundant and closely packed trees forming the environment.