-in die
Nachbarin
Always 99.4% of the 471 common nouns ending in -in take die.
Add -in to a man's job or nationality and you get a woman: der Lehrer, die Lehrerin. Always feminine.
Exceptions der Muffin
die Nachbarin
It's die Nachbarin. Nachbarin is feminine, plural die Nachbarinnen.
Die Nachbarin hilft mir.
The neighbour helps me.
Nachbarin
Always 99.4% of the 471 common nouns ending in -in take die.
Add -in to a man's job or nationality and you get a woman: der Lehrer, die Lehrerin. Always feminine.
Exceptions der Muffin