Reappear about dog (5)
I believe the answer is:
recur
'reappear' is the definition.
(thesaurus)
'about dog' is the wordplay.
'about' becomes 're' (regarding).
'dog' becomes 'cur' (cur is a kind of dog).
're'+'cur'='RECUR'
(Other definitions for recur that I've seen before include "Come round again" , "Return to mind" , "Happen repeatedly" , "Repeat" , "Happen again or repetitively" .)