also: ヘロイズム
A straightforward loanword from English 'heroism', used in the same sense of heroic conduct or qualities.
彼の行動は真のヒロイズムだ。
His actions are true heroism.
英雄主義 is the formal, kanji-based term for heroism often used in philosophical or ideological writing, while ヒロイズム is the casual loanword used in everyday or literary contexts.
ヒロイン means 'heroine' (a female protagonist), while ヒロイズム means 'heroism' (heroic conduct or spirit); learners sometimes confuse the two because of their similar katakana form.
Borrowed from English 'heroism'.