In doubt; In a state of uncertainty, or in a doubtful case. In dubio, haec legis constructio quam verba ostendunt. In a case of doubt, that is the construction of the law which the words indicate. Branch, Princ In dubio, pars mitior est sequenda. In doubt, the milder course is to be followed. In dubio, seqendum quod tutius est. In doubt, the safer course is to be adopted.