Post-structuralism and deconstruction challenge fixed meanings and objective truth in language and texts. These theories emphasize the instability of language, arguing that meaning is constantly shifting and dependent on context. They question traditional Western beliefs in stable identities and objective reality. Key thinkers like Derrida, Foucault, Barthes, and Kristeva developed concepts such as deconstruction, discourse analysis, and intertextuality. These ideas have influenced various academic fields, shaping approaches to literature, philosophy, and cultural studies. They continue to impact contemporary debates on identity, power, and meaning.