Eagle in clumsy descent (7)
I believe the answer is:
lineage
'descent' is the definition.
('lineage' can be a synonym of 'descent')
'eagle in clumsy' is the wordplay.
'clumsy' indicates anagramming the letters.
'eagle'+'in'='eaglein'
'eaglein' anagrammed gives 'LINEAGE'.
(Other definitions for lineage that I've seen before include "Genealogy" , "The strain" , "Ancestry, sequence of descendants" , "Line of descent or ancestry" , "Ancestral line as seen in eagle" .)