This is the 11071st most frequent Russian word.
глупая
Stupid.
Adjective describing 'ошибку' (mistake).
Она сделала глупую ошибку.
She made a silly mistake.
Adjective describing 'идея' (idea).
Мне кажется, это была глупая идея.
It seems to me it was a foolish idea.
Adjective describing a trait of a person in imperative mood.