Queen abandoning life's work is a worry (4)
I believe the answer is:
care
'a worry' is the definition.
(eg without a care means without a worry)
'queen abandoning life's work' is the wordplay.
'queen' becomes 'ER' (abbreviation for Elizabeth Regina).
'abandoning' is a deletion indicator.
'life's work' becomes 'career' (I've seen this before).
'career' with 'er' removed is 'CARE'.
'is' acts as a link.
(Other definitions for care that I've seen before include "Serious attention and thought" , "Safekeeping" , "Feel concern or interest" , "Prudence" , "Happy-go-lucky" .)