adjective

lacking a plan, purpose, or enthusiasm.

a few people were left, dancing in a desultory fashion

casual,half-hearted,lukewarm,cursory,superficial,token,perfunctory,passing,incidental,sketchy,haphazard,random,aimless,rambling,erratic,unmethodical,unsystematic,automatic,unthinking,capricious,mechanical,offhand,chaotic,inconsistent,irregular,intermittent,occasional,sporadic,inconstant,fitful