to makecontinuous,smallmovements,especiallyif they do not have aparticularpurposeand you make them withoutmeaningto, forexamplebecause you arenervousorbored:
Children can'tsitstill forlongwithout fidgeting.
Heclearedhisthroatandnervouslyfidgeted with apencil.
He fidgets with astringofworrybeads.