Customer runs into no bar backwards (6)
I believe the answer is:
patron
'customer' is the definition.
(a customer of a business or service)
'runs into no bar backwards' is the wordplay.
'runs' becomes 'r' (cricket abbreviation).
'into' is an insertion indicator.
'bar' becomes 'tap' (short for taproom).
'backwards' says the letters should be written backwards.
'no'+'tap'='notap'
'r' inserted into 'notap' is 'nortap'.
'nortap' written backwards gives 'PATRON'.
(Other definitions for patron that I've seen before include "One who protects" , "manager (13) [FRENCH]" , "Saint" , "Regular customer; backer" , "one of the regular customers" .)