This is the 10226th most frequent Polish word.
bystra
"Bystra" means "bright," "quick-witted," or "sharp" in English.
Here, 'bystra' is used as an adjective describing the noun 'uczennicą' (student), meaning 'bright' or 'quick-witted'.
Ona jest bardzo bystrą uczennicą i szybko się uczy.
She is a very bright student and learns quickly.
Here, 'bystra' describes the noun 'rzeka' (river), referring to its speed or swiftness in the context of flow.
Rzeka w tym miejscu jest niezwykle bystra.
The river at this place is extremely swift.
Here, 'bystra' is in the context of 'spojrzenie' (gaze), implying keen or perceptive observative quality.