Family in yard turned unpleasant (7)
I believe the answer is:
dynasty
'family' is the definition.
(I know that dynasty is a type of family)
'yard turned unpleasant' is the wordplay.
'yard' becomes 'yd' (abbreviation).
'turned' says the letters should be written backwards.
'unpleasant' becomes 'nasty' (nasty can mean unpleasant or horrible).
'yd' written backwards gives 'dy'.
'dy'+'nasty'='DYNASTY'
'in' is the link.
(Other definitions for dynasty that I've seen before include "Family line of rulers" , "Ruling sequence" , "show" , "royal family" , "Song, say" .)