Not “tearing apart”, one's gathered! (11)
I believe the answer is:
integration
'not tearing apart one's gathered' is the definition.
I can't tell whether this definition defines the answer.
'not tearing apart one's gathered' is the wordplay.
'apart' is an anagram indicator.
'one' becomes 'i' (roman numeral).
'gathered' means one lot of letters goes inside another.
'not'+'tearing'='nottearing'
'nottearing' is an anagram of 'integraton'.
'integraton' placed around 'i' is 'INTEGRATION'.
(Another definition for integration that I've seen is " Process of combining".)