They were 'cowed' into silence by threats. [=they did not complain, publicly say anything, etc., because they had been threatened]
They'll be arguing about this 'till the cows come home'.
The football team was a 'cash cow' for the university.
(..) and we've had idiot kings, but I don't know if we've ever been cursed with a vicious idiot for a king. - You can't-- - I can, I am. They attacked me! They threw a cow pie at you, so you decided to kill them all? They're starving, you fool. All because of a war you started. You're talking to a king! (..)2012 TvShow: Game of Thrones Title: The Old Gods and the New Season: 2 Episode 6