Figuring out the right words for paternal and maternal aunts and uncles isn't actually that confusing if one analyze the words.
Farbror = far + bror ("father's brother") Morbror = mor + bror ("Mother's brother") Moster = mor + (sy)ster ("mother's sister") Faster = far + (sy)ster ("father's sister")
Well kind of, for example a child can say "Jag tycker inte om den där farbrorn. Han är en dum farbror." = I do not like that man. He is a stupid man. A grownup would probably use "mannen" eller "karln" instead of farbrorn. But sometimes even grownup can use it, but mostly its when we talk to children, I think.
Same with "tanten". You could use "tanten"/"tant" instead of farbrorn/farbror in the sentence abowe. More used with children to refer to an older women. But I could say that girl has really turned into a old lady = "Den där tjejen har verkligen blivit en tant".
But you don't use faster/moster instead of tant. But you could use "gubben/gubbe" instead of "farbrorn/farbror".
Hope this helped some!
While all of the above directly translate to "aunt", Swedish has paternal & maternal words. (Words for the father's side and for the mother's side).
Faster is derived from far + syster. (Father's sister)
Moster is derived from mor + syster. (Mother's sister)
You use the different words depending on which side of the family you are talking about, father's or mother's. If you are talking about your aunt from your mom's side of the family, you would use moster.
Like ALXNDRH mentioned above, "tant" is a more informal and derogatory remark, similar to "gubbe".