Aufgabe - auf is above, gabe is give, so aufgabe (work, job) is that which is given from above, either from your boss, parent, or god. Because if you choose to do it, it is not work, it’s play. But if it’s given from above - then it is work!
überlegen - über is over, and legen is to lay. So over-laying something, to lay over something. When you’re thinking about something hard, you are laying on it. And so the meaning is to reflect, to ponder, to think hard on something.
Gemeinschaft - Gemein- is a root that means common. Gemeine is a commoner (noun), Gemeinsam is common (adjective). Schaft means shaft, or stem, or stock. So it means that it all belongs to the common stem. Together it means a community, or a collective. You will see it also with Wohngemeinschaft (Wohn being residential) meaning residential+community = shared appartment. Or Lebensgemeinschaft (Leben being life) so Life+community = shared life (usually reffered to a couple living together in the same house but not married).
Unterscheid - unter is under, schied or scheid are words meaning sides, or parts (Scheide means vagina, or a scabbard - because it has two opposite sides; Scheiden means parting), and together this means “difference”. So under+parting means difference. It’s kind of like all things are parted in this world, but if you want to see or understand their difference, you have to find the under-parting, or the underlying “ruler” in which you can explain their difference. Schiedsmann or Schiedsrichter means arbiter (parts-man or parts-judge), i.e. the person responsible for the opposite sides.