Den raised after a bit of excitement in the air (6)
I believe the answer is:
aerial
'air' is the definition.
('aerial' can be similar in meaning to 'air')
'den raised after a bit of excitement' is the wordplay.
'den' becomes 'lair' ('lair' can be a synonym of 'den').
'raised' says the letters should be written backwards.
'after' is a charade indicator (letters next to each other).
'bit of' indicates taking the first letters.
The initial letter of 'excitement' is 'e'.
'lair' backwards is 'rial'.
'a'+'e'='ae'
'rial' after 'ae' is 'AERIAL'.
'in the' acts as a link.
(Other definitions for aerial that I've seen before include "It picks up radio waves" , "Device to receive or transmit radio waves" , "Antenna; of the air" , "Device for sending or receiving signals" , "Radio waves receiver" .)