Well-ventilated and sprightly (4)
I believe the answer is:
airy
This clue is a double definition.
'well-ventilated' is the first definition.
(something well-ventilated has lots of fresh air)
'sprightly' is the second definition.
(I've seen this before)
'and' acts as a link.
(Other definitions for airy that I've seen before include "Old astronomer" , "Spacious; nonchalant" , "Sprightly" , "Delicate; dismissive" , "Light and insubstantial" .)