This is the 14186th most frequent German word.
grob
Coarse; rough; rude.
In this sentence, 'grob' describes someone's behavior as 'rude' or 'impolite'.
Er war so grob zu uns, dass wir uns unwohl fühlten.
He was so rude to us that we felt uncomfortable.
Here, 'grob' is applied to describe the texture of the sand as 'coarse'.
Der Sand fühlte sich grob an, als ich ihn in meiner Hand hielt.
The sand felt coarse as I held it in my hand.
Here, 'grob' is used as an adjective meaning 'rough' or 'not detailed'.