du

dubious (adj.) doubtful, of uncertain quality (Suspicious that he was only trying to get a raise, she found his praise dubious.)

duplicity (n.) crafty dishonesty (His duplicity involved convincing his employees to let him lower their salaries and increase their stock options, and then to steal the money he saved and run the company into the ground.)

duress (n.) hardship, threat (It was only under intense duress that he, who was normally against killing, fired his gun.)