Full of hot air (5)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">full of hot air</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for gassy that I've seen before include "Verbose" , "Fizzy" , "Carbonated" .)