Worrying area I observed in review of next year (7)
I believe the answer is:
anxiety
'worrying' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'area i observed in review of next year' is the wordplay.
'area' becomes 'a' (maths abbreviation).
'observed in' means one lot of letters goes inside another.
'review of' is an anagram indicator.
'year' becomes 'y'.
'next' anagrammed gives 'nxet'.
'i' inserted inside 'nxet' is 'nxiet'.
'a'+'nxiet'+'y'='ANXIETY'
Can you help me to learn more?
(Other definitions for anxiety that I've seen before include "State of apprehension" , "Morbid unease" , "Disquiet" , "tension" , "Worried state" .)