Ancestry Neil concocted over period of time (7)
I believe the answer is:
lineage
'ancestry' is the definition.
(synonyms)
'neil concocted over period of time' is the wordplay.
'concocted' indicates an anagram.
'over' says to put letters next to each other.
'period of time' becomes 'age' (age is a kind of period of time).
'neil' is an anagram of 'line'.
'line'+'age'='LINEAGE'
(Other definitions for lineage that I've seen before include "Ancestral line as seen in eagle" , "Line of descent or ancestry" , "Ancestry, sequence of descendants" , "Pedigree, family tree" , "Direct descent" .)