King George etc, ignoring old descendant (8)
I believe the answer is:
grandson
'descendant' is the definition.
(I know that descendant can be written as grandson)
'king george etc ignoring old' is the wordplay.
'king george' becomes 'gr' (Georgius Rex).
'etc' becomes 'and so on' (I've seen this before).
'ignoring' is a deletion indicator.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'andsoon' with 'o' taken away is 'andson'.
'gr'+'andson'='GRANDSON'
(Other definitions for grandson that I've seen before include "Young male descendant" , "issue for daughter, perhaps" , "Dons rang (anag) - relative" , "Younger male relative" , "Junior relative" .)