Common sense keeps the Queen very worried (7)
I believe the answer is:
nervous
'worried' is the definition.
(thesaurus)
'common sense keeps the queen very' is the wordplay.
'common sense' becomes 'nous' (nous is a kind of common sense).
'keeps' means one lot of letters goes inside another.
'the queen' becomes 'er' (Elizabeth Regina).
'very' becomes 'v' (abbreviation).
'er'+'v'='erv'
'nous' placed around 'erv' is 'NERVOUS'.
(Other definitions for nervous that I've seen before include "Jumpy" , "Fearful or apprehensive" , "Twitchy" , "Fidgety" , "Worried, apprehensive" .)