[tmi]

So there's the saying "blood is thicker than water".

Which ACTUALLY means the opposite of what it's usually taken to mean, since

the full quote is "the blood of the covenant is thicker than the water of the womb".

Now, I don't know about water, but I find that the blood of the womb is in fact rather thicker than what you might call the blood of the vein.

Discuss implications for idiomatic accuracy.

well "the water of the womb" refers literally to amniotic fluid which is I'm pretty sure a fairly thin liquid

shhhh I'm pretending to be witty about the fact that my life is fucking gross

also I've never seen amniotic fluid - well, the once obviously, but I was distracted - and thus don't have much basis for comparison.