Frivolous, scatterbrained (7)
I believe the answer is:
flighty
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">frivolous</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >'<span class="explanation-format__original">scatterbrained</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that scatterbrained can be written as flighty)</span><br/ ><br/ ></span>
(Other definitions for flighty that I've seen before include "Mentally giddy, in an aerial way perhaps" , "Giddy-minded" , "Frivolous - irresponsible" , "Capricious" , "Fickle; erratic" .)