This is the 2708th most frequent Polish word.
dobrych
"Good" in plural genitive or plural accusative forms.
The word 'dobrych' is in the genitive plural form of the adjective 'dobry,' agreeing with the genitive plural noun 'książek'.
On ma wiele dobrych książek.
He has many good books.
Here, 'dobrych' is the genitive plural form of the adjective 'dobry,' matching the genitive plural noun 'rad' to indicate the characteristic of the advice.
Potrzebuję kilku dobrych rad.
I need some good advice.
In this sentence, 'dobrych' is the accusative plural form of the adjective 'dobry,' modifying the plural noun 'ludzi,' which is in the accusative case as a direct object.