Dicky, Ron, Peg and Arthur’s family (9)
I believe the answer is:
pendragon
'arthur's family' is the definition.
(surname of King Arthur)
'dicky ron peg and' is the wordplay.
'dicky' indicates an anagram (dicky can mean ill or non-functioning).
'ron'+'peg'+'and'='ronpegand'
'ronpegand' with letters rearranged gives 'PENDRAGON'.
(Other definitions for pendragon that I've seen before include "King Arthur, for example" , "Uther --" , "Tribal chief," , "Ruler" , "old British chief" .)