Posh prince before performance shows sign of improvement (6)
I believe the answer is:
upturn
'sign of improvement' is the definition.
'upturn' can be an answer for 'improvement' (upturn is a kind of improvement). I am unsure of the 'sign of' bit.
'posh prince before performance' is the wordplay.
'posh' becomes 'u' (abbreviation for upper-class - opposite to non-u).
'prince' becomes 'p'.
'before' is a charade indicator (letters next to each other).
'performance' becomes 'turn' (turn is a kind of performance).
'u'+'p'+'turn'='UPTURN'
'shows' acts as a link.
Can you help me to learn more?
(Other definitions for upturn that I've seen before include "Recovery" , "Improvement, better trend in business" , "Rise" , "Improvement, in business say" , "Boom after a bust" .)