They're up in the air and clamorous in the Civil Service (6)
I believe the answer is:
clouds
'they're up in the air' is the definition.
The definition suggests an adverb but the answer is not.
'clamorous in the civil service' is the wordplay.
'clamorous' becomes 'loud' (I've seen this in another clue).
'in the' means one lot of letters goes inside another.
'civil service' becomes 'CS' (abbreviation).
'loud' inserted within 'cs' is 'CLOUDS'.
'and' is the link.
Can you help me to learn more?
(Other definitions for clouds that I've seen before include "obfuscates" , "''I've looked at .... that way'' (Joni Mitchell)" , "Makes less transparent" , "Visible masses suspended at considerable altitude" , "becomes opaque" .)