This is the 11208th most frequent Polish word.
groźną
"Groźną" means "threatening" or "dangerous" in English.
In this sentence, 'groźną' is an adjective in its feminine instrumental singular form, describing 'burzą' (storm). It denotes something threatening or dangerous.
Widok groźną burzą zaskoczył nas na plaży.
The sight of the threatening storm surprised us on the beach.
Here, 'groźną' serves as an adjective in its feminine instrumental singular form, modifying 'sytuacją' (situation), and implies a serious or intimidating circumstance.
Podeszliśmy ostrożnie do groźną sytuacją w biurze.
We approached cautiously the threatening situation in the office.
'Groźną' again appears as a feminine instrumental singular form, this time linked to 'twarz' (face), indicating a menacing demeanor.