This is the 8635th most frequent Russian word.
осторожной
"Careful" or "cautious."
The word 'осторожной' is used as an adjective in the instrumental case, describing the subject (she) and indicating her cautious behavior.
Она всегда была очень осторожной в принятии решений.
She has always been very cautious in making decisions.
Here, 'осторожной' is an adjective matching the subject's state (me) in the instrumental case, showing guidance towards cautiousness.
Его советы помогли мне быть более осторожной.
His advice helped me to be more careful.
In this sentence, 'осторожной' appears in the instrumental case, reflecting the advised state or manner of behavior (carefulness).