This is the 12157th most frequent German word.
unterwäsche
Underwear.
In this sentence, 'Unterwäsche' is used as a direct object representing clothing items purchased.
Ich habe gestern neue Unterwäsche gekauft.
I bought new underwear yesterday.
Here, 'Unterwäsche' is the subject of the verb 'wechseln,' referring to maintaining hygiene.
Man sollte regelmäßig seine Unterwäsche wechseln.
One should regularly change their underwear.
In this case, 'Unterwäsche' is described with a material, discussing its qualities as an item of clothing.