Performer about to hold up a performer (7)
I believe the answer is:
acrobat
'performer' is the definition.
(I have seen 'Gymnastic performer ' mean 'acrobat' so perhaps 'performer' could also mean 'acrobat')
'performer about to hold up a' is the wordplay.
'performer' becomes 'act' (someone with an act).
'about' means one lot of letters goes inside another.
'to hold up' becomes 'rob' (as in holding up a bank).
'rob'+'a'='roba'
'act' placed around 'roba' is 'ACROBAT'.
(Other definitions for acrobat that I've seen before include "Gymnastic entertainer" , "Boat car (anag.)" , "Circus athlete" , "Agile circus performer" , "circus artiste" .)