adj.普通的，无关紧要的；adj.不严肃的
Merriam-Webster Online Dictionary
frivolous (adjective)1.
a) of little weight or importance
b) having no basis (as in fact or law) - sound a frivolous lawsuit
2.
a) lacking in seriousness
b) marked by unbecoming - levity
Merriam-Webster Online Thesaurus
frivolous (adjective)1.
lacking importance
SYNONYMS:
fiddling, foolish, frivolous, incidental, inconsequential, inconsiderable, insignificant, little, Mickey Mouse, minor, minute, negligible, nugatory, slight, small, small-fry, trifling, trivialRELATED WORDS:
jerkwater, one-horse; nickel-and-dime, paltry, petty, small-time, worthless; anonymous, nameless, obscure, uncelebrated, unknownNEAR ANTONYMS:
decisive, fatal, fateful; chief, dominant, overbearing, overmastering, overriding, principal; distinctive, exceptional, impressive, outstanding, prominent, remarkable; valuable, worthwhile, worthy; distinguished, eminent, great, illustrious, preeminent, prestigious; famous, notorious, renowned; all-important, basic, essential, fundamental, key2.
lacking in seriousness or maturity
SYNONYMS:
birdbrained, ditzy ( ditsy), dizzy, featherbrained, flighty, frivolous, frothy, futile, goofy, harebrained, light-headed, light-minded, puerile, scatterbrained, silly, yeastyRELATED WORDS:
fatuous, foolish, inane, nonsensical, thoughtless, witless; crazy, daffy, daft, fruity; exuberant, flippant, fluttery, giggly, happy, light, lighthearted, playful; sappy, shallow, superficialNEAR ANTONYMS:
grave, melancholy, somber ( sombre), thoughtful; dignified, heavy, no-nonsense, sedate, severe, solemn, staid