What does "postmodernism" mean?

Any style in art, architecture, literature, philosophy, etc., that reacts against an earlier modernist movement.

How do you pronounce "postmodernism"?

Pronounced //pəʊstˈmɑdɚnɪzəm//.

/pəʊstˈmɑdɚnɪzəm/ noun

noun ·Rare ·Advanced level

Noun

1
Any style in art, architecture, literature, philosophy, etc., that reacts against an earlier modernist movement. uncountable, usually
2
genre of art and literature and especially architecture in reaction against principles and practices of established modernism wordnet
3
An attitude of skepticism or irony toward modernist ideologies, often questioning the assumptions of Enlightenment rationality and rejecting the idea of objective truth. uncountable, usually
"The most famous definition of postmodernism is Lyotard's: “I define postmodern as incredulity towards metanarratives.” […] To accept Lyotard's definition of postmodernism is to accept the premise that postmodernism is the first movement since the Enlightenment to think critically about such narratives."

"Yona Wallach had been a postmodernist two decades before the term "Postmodernism" was even conceived."

From post- + modernism.