Is appearing in better act with zero rehearsal (9)
I believe the answer is:
improvise
'is appearing in better act with zero rehearsal' is the definition.
I can't judge whether this defines the answer.
'is appearing in better' is the wordplay.
'appearing in' means one lot of letters goes inside another.
'better' becomes 'improve' (synonyms).
'is' inserted into 'improve' is 'IMPROVISE'.
Can you help me to learn more?
(Other definitions for improvise that I've seen before include "Create without preparation" , "Ad-lib" , "Perform without preparation" , "Act without previous planning" , "Quickly make changes" .)