Boasting of a daughter in good show (7)
I believe the answer is:
bravado
'boasting' is the definition.
(I've seen this before)
'a daughter in good show' is the wordplay.
'daughter' becomes 'd' (genealogical abbreviation).
'in' means one lot of letters goes inside another.
'good show' becomes 'bravo'.
'a'+'d'='ad'
'ad' going into 'bravo' is 'BRAVADO'.
'of' is the link.
(Other definitions for bravado that I've seen before include "Swaggering confidence" , "Daring to impress" , "A show of boldness, may be phoney" , "Boastful courage" , "Rash display of courage" .)