Bailey's circus partner (6)
I believe the answer is:
barnum
'bailey's circus partner' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for barnum that I've seen before include "US creator of "The Greatest Show On Earth"" , "With Bailey, he ran a famous circus" , "US showman who popularized the circus" , "19th century US showman" , "PT ______, American showman" .)