Why is it der Individualismus?

Individualismus ends in -ismus, and nouns ending in -ismus are masculine: in a German dictionary, 100% of them take der.

All nouns ending in -ismus
Sense 1
der

Meaning

[1] Setting/attitude that particularly emphasizes the possibilities of development of the individual

[1] Einstellung/Haltung, die die Entfaltungsmöglichkeiten des Individuums besonders hervorhebt

Examples

[1] "The private car is an out -of -date individualism"

[1] „Das Privatauto ist unzeitgemäßer Individualismus.“

[1] "Individualism, on the other hand, led to the Degree" "

[1] „Individualismus hingegen führte zum Ableben.“

Declension

1 Singular Plural
Nominativ der Individualismus —
Genitiv des Individualismus —
Dativ dem Individualismus —
Akkusativ den Individualismus —

Pronunciation

Dictionary entries include material from Wiktionary. Wiktionary