This is the 16508th most frequent Polish word.
wierną
"Faithful" or "loyal."
Here, 'wierną' is used as an adjective to describe the friend's loyalty and faithfulness.
Zawsze była wierną przyjaciółką.
She was always a faithful friend.
In this sentence, 'wierną' describes the steadfast and committed nature of the membership.
Została wierną członkinią naszego klubu.
She became a loyal member of our club.
Here, 'wierną' characterizes someone who steadfastly adheres to their beliefs.