Vertical part shown, cannot reveal side (7)
I believe the answer is:
everton
'side' is the definition.
'vertical part shown cannot reveal' is the wordplay.
'vertical' says the letters should be written backwards.
'part' indicates a hidden word.
'notreve' can be found hidden inside 'shown cannot reveal'.
'notreve' back-to-front is 'EVERTON'.
(Other definitions for everton that I've seen before include "Merseyside soccer team" , "Merseyside football club" , "Liverpool FC" , "Merseyside football team" , "One side in blue" .)