Frivolous (7)
'frivolous' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for trivial that I've seen before include "Of little consequence" , "Inconsequential, too minor to be bothered about" , "Meaningless" , "not significant" , "Worthless" .)
'frivolous' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for flighty that I've seen before include "Frivolous - irresponsible" , "Fickle; erratic" , "Changeable" , "Giddy-minded" , "rather impetuous?" .)
'frivolous' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for empty-headed that I've seen before include "Unintelligent, stupid" , "Vacuous" , "Scatterbrained" , "Frivolous" , "Given to frivolity" .)