In Catholic moral theology and philosophy, lying is considered a sin, even if it serves a higher purpose, like saving a family from the Stasi. (I thought I’d choose someone else than the Nazis for this.) But as far as I know, they do make a crucial distinction between deceit and lying. This distinction holds that ‘lying’ is to ‘deceit’ what ‘murder’ is to ‘killing.’ (‘Deceit’ and ‘killing’ being genera; ‘lying’ and ‘murder’ being species.)
Killing is not always wrong, for example in self defense. Murder, however, is always wrong. Same with deceit and lying. It’s not always wrong to deceit someone (being silent, not telling everything, using sarcasm, etc.), while it is wrong to outright lie.
It seems to me that many fail to make this crucial distinction between ‘lying’ and ‘deceit,’ just like some (for instance in discussions concerning just war, self defense, etc.) fails to make the crucial distinction between ‘murder’ and ‘killing.’ So no, I do not think that deceit equals lying. But am I right?