Pops to meet wise guy in alley (7)
I believe the answer is:
passage
'alley' is the definition.
(I've seen this before)
'pops to meet wise guy' is the wordplay.
'pops' becomes 'pas' ('pa' can be a synonym of 'pop').
'to meet' is a charade indicator (letters next to each other).
'wise guy' becomes 'sage'.
'pas'+'sage'='PASSAGE'
'in' is the link.
(Other definitions for passage that I've seen before include "Way through; part of text" , "Sea/air journey" , "Section of musical or literary work" , "Piece of text or music" , "Transit - part of book etc" .)