Ethereal tiny ad designed (6)
I believe the answer is:
dainty
'ethereal' is the definition.
(thesaurus)
'tiny ad designed' is the wordplay.
'designed' indicates anagramming the letters (designed with the letters).
'tiny'+'ad'='tinyad'
'tinyad' is an anagram of 'DAINTY'.
(Other definitions for dainty that I've seen before include "Petite and elegant" , "sensitive" , "Piece of cake!" , "Delicate, neat" , "Small and pretty, delicate" .)