To be intent and serious to the point of callousness; play hardball: We're out here man for man and playin' for keeps
[1861+; fr the game of marbles and other children's games where the tokens may be either returned or kept by the winner]
The only answer, according to his closest advisors, was to play rough.
I knew better than to play rough, so I just looked down at his hand, and didn't stop looking at it until he took it away.
Poor Rabbit had been educated at home by a foolish, widowed mother, who had been afraid of letting him play rough games.
Now that, seor, should teach you not to play rough with a red-head.
I dare not trust myself to play rough with men, let alone boys—yes, I didn't dare strike.
"And they'll play rough to stop us from finding it," Arv added forebodingly.