D defs.my
Entry 2 senses Webster, 1913

Frivolous

/frĭv'-əl-əs/ · Friv·o·lous · IPA /ˈfɹɪv.ə.ləs/
01 a. Of little weight or importance; not worth notice; slight; as, a frivolous argument.
  1. 1.
    Of little weight or importance; not worth notice; slight; as, a frivolous argument.
  2. 2.
    Given to trifling; marked with unbecoming levity; silly; interested especially in trifling matters.
    “His personal tastes were low and frivolous.” Macaulay.