Genial Dicky initially enjoyed descent (7)
I believe the answer is:
lineage
'descent' is the definition.
(synonyms)
'genial dicky initially enjoyed' is the wordplay.
'dicky' indicates an anagram (dicky can mean ill or non-functioning).
'initially' indicates taking the first letters.
The initial letter of 'enjoyed' is 'e'.
'genial' is an anagram of 'lineag'.
'lineag'+'e'='LINEAGE'
(Other definitions for lineage that I've seen before include "The strain" , "Ancestry, sequence of descendants" , "Descent from ancestors" , "Line of descent or ancestry" , "Stock" .)