Broadly, retraction is the withdrawal of an article from publication for whatever reason by the author or publisher. The reasons for the retraction are usually given in a Retraction Notice. This is published in the journal with the retracted journal article.
The most widely accepted definition is provided by Committee on Publication Ethics (COPE) Retraction Guidelines 2019,
“Retraction is a mechanism for correcting the literature and alerting readers to articles that contain such seriously flawed or erroneous content or data that their findings and conclusions cannot be relied upon."