From Longman Dictionary of Contemporary Englishnot in (all/good) consciencenot in (all/good) conscienceformalBAD BEHAVIOUR OR ACTIONS if you cannot in all conscience do something, you cannot do it because you think it is wrong I couldn’t in all conscience tell him that his job was safe. → conscience
Examples from the Corpus
not in (all/good) conscience• I have a hard time separating one statement resulting from torture from another and I can not in good conscience do so.• And apologists for Labour's refusal to organise in Northern Ireland can not in all conscience describe themselves as democrats.• Yet as Dunkers they could not in conscience support the use of force or pay disrespect to the Crown.