fanaticism
n. uncountable C1 Advanced US //fəˈnætəˌsɪzəm// UK //fɐnˈætɪsˌɪzəm// fa·nati·cism
n. extreme and uncontrolled enthusiasm for a belief, idea, or activity. It often involves ignoring facts or being too focused on one thing.
n. extreme and unreasoning devotion to a cause, belief, or interest. Often carries a negative connotation of irrationality or an inability to consider alternative perspectives.
His fanaticism for football makes him ignore the team's poor performance.
The politician's speech was criticized for promoting fanaticism rather than encouraging a balanced debate on the new law.
While the movement began as a call for reform, its rapid growth into fanaticism eventually led to the exclusion of any members who dared to question the central tenets.
From fanatic + -ism.