Light and spacious (4)
I believe the answer is:
airy
'light and spacious' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for airy that I've seen before include "(Of ideas) speculative" , "Spacious; nonchalant" , "Well ventilated; insubstantial" , "Well-ventilated; delicate" , "Flippant" .)