Most rhythm emphasises the strong beats of a bar. Syncopation shifts emphasis onto the off-beats, making music feel like it is leaning or bouncing. Funk, reggae, Latin music, jazz and Afrobeats are all deeply syncopated.
A simple example is a chord that lands just before the beat rather than on it, a push that drives energy forward.
Using it in a prompt
Ask for "syncopated bass" or "off-beat chords" to add groove. Words like "bouncy" and "funky" usually lead to more syncopation.