(1)showing lack of careful thought; "the debate turned into thoughtless bickering"
(2)熟考の欠乏の提示
(3)lacking seriousness; given to frivolity; "a dizzy blonde"; "light-headed teenagers"; "silly giggles"
(4)真剣さを欠いているさま
(5)軽薄な傾向がある
(1)