What are accented notes that run against the regular pulse of the musical meter referred to as?

Accented notes that run against the regular pulse of the musical meter are referred to as "syncopation." Syncopation creates a feeling of rhythmic surprise by placing emphasis on beats or parts of beats that are typically unaccented, resulting in a more dynamic and expressive musical experience. This technique is commonly used in various musical genres to enhance the groove and drive of a piece.