light-minded
adjective
light-mind·ed ˈlīt-ˌmīn-dəd 
: lacking in seriousness : frivolous
light-mindedly adverb
light-mindedness noun
Synonyms
- birdbrained
- ditzy
- ditsy
- dizzy
- featherbrained
- flighty
- frivolous
- frothy
- futile
- giddy
- goofy
- harebrained
- light-headed
- puerile
- scatterbrained
- silly
- yeasty
See all Synonyms & Antonyms 
Word History
First Known Use
circa 1529, in the meaning defined above
light-mindedness
noun
as in lightness
a lack of seriousness often at an improper time she displays a light-mindedness that might be excusable in a teenager but not in someone hoping to make it in the business world Synonyms & Similar Words
Relevance
- lightness
- glee
- cheerfulness
- silliness
- flippancy
- frivolousness
- facetiousness
- levity
- frivolity
- cheer
- festivity
- high-spiritedness
- frothiness
- flightiness
- mirthfulness
- mirth
- childishness
- goofiness
- light-headedness
- hilarity
- lightheartedness
- merriment
- joviality
- gleefulness
- gaiety
- puerility
- gayety
Antonyms & Near Antonyms
- gravity
- seriousness
- earnestness
- solemnity
- soberness
- sadness
- unhappiness
- depression
- melancholy
- gloom
- dejection
- solemnness
- moroseness
- dispiritedness
- gloominess
- sullenness
- despondency
- heartsickness
- joylessness
- downheartedness
- mopes