UPA perhaps without former stability (7)
I believe the answer is:
plateau
'stability' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'upa perhaps without former' is the wordplay.
'perhaps' indicates anagramming the letters.
'without' indicates putting letters inside ('without' can be similar in meaning to 'outside').
'former' becomes 'late' ().
'upa' is an anagram of 'pau'.
'pau' enclosing 'late' is 'PLATEAU'.
Can you help me to learn more?
(Other definitions for plateau that I've seen before include "Area of level high ground" , "High flattish area" , "Area of livel high ground" , "relatively flat territory" , "Flat raised land" .)