Feel the MPs are worried about nothing (10)
I believe the answer is:
atmosphere
'feel' is the definition.
(thesaurus)
'the mps are worried about nothing' is the wordplay.
'worried' indicates anagramming the letters.
'about' is an insertion indicator.
'nothing' becomes 'o' (looks like zero - 0).
'the'+'mps'+'are'='thempsare'
'thempsare' with letters rearranged gives 'atmsphere'.
'atmsphere' enclosing 'o' is 'ATMOSPHERE'.
(Other definitions for atmosphere that I've seen before include "Spirit" , "prevailing mood" , "climate" , "Gas surrounding a planet" , "Pervading tone or mood" .)