Learn German: Ein älterer Herr wohnt in dem neuen Seniorenheim. - An elderly gentleman lives in the new retirement home.

This is an example of the absolute comparative (Absoluter Komparativ). Instead of comparing two things (like "older than me"), German uses the comparative form to soften an adjective. Here, ein älterer Herr doesn't mean he is older than someone else; it simply means he is "elderly" or "quite old."

Is an älterer Herr older or younger than an alter Herr?

Surprisingly, an älterer Herr is generally a bit younger than an alter Herr! Because the absolute comparative is used to soften the meaning, älter (elderly/older) is less extreme than alt (old). It is a polite way to say someone is getting on in years without calling them flat-out "old."

Why does the adjective have a double -er at the end (älterer)?

The base comparative adjective is älter. Because it modifies a masculine noun (Herr) in the nominative case, and follows the indefinite article ein (which lacks a gender-revealing ending here), the adjective itself must take the strong masculine nominative ending -er. So, you get älter + -er = älterer.

Why do we use the dative case (in dem neuen) instead of the accusative (in das neue)?