Blush regarding daughter being found in lair (6)
I believe the answer is:
redden
'blush' is the definition.
(synonyms)
'regarding daughter being found in lair' is the wordplay.
'regarding' becomes 're' (re can mean regarding, concerning).
'daughter' becomes 'd' (genealogical abbreviation).
'being found in' means one lot of letters goes inside another.
'lair' becomes 'den' (synonyms).
'd' inserted within 'den' is 'dden'.
're'+'dden'='REDDEN'
(Other definitions for redden that I've seen before include "Give visible sign of embarrassment" , "Flush, become embarrassed" , "Reveal embarrassment in colourful way" , "Blush like the dawn sky" , "Evaluate the nature of (something)" .)