Figure in performing arts taking pessimistic view (2,5)
I believe the answer is:
at worst
'taking pessimistic view' is the definition.
(in the worst case...)
'figure in performing arts' is the wordplay.
'figure' becomes 'two' (two is a number).
'in' indicates putting letters inside.
'performing' is an anagram indicator (the letters move around or 'perform').
'arts' with letters rearranged gives 'arst'.
'two' going within 'arst' is 'AT WORST'.
(Other definitions for at worst that I've seen before include "In the most negative circumstances" , "Taking the most pessimistic view" , "Taking blackest view" , "in the most serious state" , "most pessimistically" .)