WordNet sense 1 (a detail that is considered insignificant):

technicality, triviality

WordNet sense 2 (something of small importance):

trivia, small beer

WordNet sense 3 (waste time; spend one's time idly or inefficiently):

piddle, wanton, piddle away, wanton away

WordNet sense 4 (act frivolously):

frivol

WordNet sense 5 (consider not very seriously):

dally, play