Show the lady is playing the piano inside (7)
I believe the answer is:
display
'show' is the definition.
(display can mean to show or expose)
'lady is playing the piano inside' is the wordplay.
'playing' indicates anagramming the letters.
'the piano' becomes 'p' (musical abbreviation).
'inside' indicates putting letters inside.
'lady'+'is'='ladyis'
'ladyis' anagrammed gives 'dislay'.
'dislay' going around 'p' is 'DISPLAY'.
'the' acts as a link.
(Other definitions for display that I've seen before include "Show to the public" , "Demonstrate, show" , "Place on show" , "Put on show" , "Showcase" .)