Worry about Liberal's quality (7)
I believe the answer is:
calibre
'quality' is the definition.
(I know that quality can be written as calibre)
'worry about liberal's' is the wordplay.
'worry' becomes 'care' (eg without a care means without a worry).
'about' indicates putting letters inside.
'liberal' becomes 'lib'.
'care' placed around 'lib' is 'CALIBRE'.
(Other definitions for calibre that I've seen before include "Quality - gun barrel bore" , "Ability; barrel diameter" , "Bullet size" , "Personal character" , "Level of ability; bore" .)