Is it the equivalent of to hit somebody where it hurts? To do or say something to someone in order to upset them as much as possible and hurt somebody where they will feel it most?
I could say: not always - you can hit somebody in this point completely accidentaly. Or this point can be e.g. his sense of responsibility and he will do something when he is not in mood, but it will not hurt him a lot :-)
Yes and no: sb pretends a nice person when suddenly it is revealed he/she isn`t and then the comment is uttered. Herbs can have either healing or poisonous properties.
Not ' pretend to be a holy person?' Doesn't quite make sense to me. Does it mean someone who tries to be someone else with the intention to deceive? Or someone who is holier than thou, a hypocrite?
Yes, except it`s not about money, but things which are considered of little worth.
Besides, last year I learnt its deeper meaning - to hide and then forget where you put it, just like real hamsters do in nature - they are able to collect 50 kilograms of grain and never use it all through winter.
No, one is enough. Various sources say from 15 to 60 kg. rzeplin.pl/c-d-chomik-europejski/
BTW, I recalled the idiom cause hamsters have returned to our area. I found a young one on the drive, probably killed by cats at night. My kids found a giant hole under the bush nearby.