Some comparative forms are used to express something that has a contrary meaning of what the word itself says.
Example
alt = älter
old = older
Ein älterer
Mann trank ein Bier.
An elderly man was drinking beer.
One could think that älterer
means that the man is older than just old. This is not the case. It actually means that this person is not yet old, but older than young.
The other way around it does not work the same way. Jüngerer still means younger than just simply young.
