Sing in picturesque alleyway (6)
I believe the answer is:
squeal
'sing' is the definition.
(thesaurus)
'in picturesque alleyway' is the wordplay.
'in' says the answer is hidden in the clue.
'SQUEAL' is hidden in the letters of 'picturesque alleyway'.
(Other definitions for squeal that I've seen before include "Study of plants" , "Make shrill noise like stuck pig" , "Squeak; inform" , "Cry -- snitch" , "Screech" .)