Shopper needs carrier taking drink outside (8)
I believe the answer is:
betrayer
'shopper' is the definition.
(I've seen this before)
'carrier taking drink outside' is the wordplay.
'carrier' becomes 'tray' (I've seen this before).
'taking drink' becomes 'beer' (beer is a kind of drink. I am not sure about the 'taking' bit.).
'outside' means one lot of letters goes inside another (some letters go outside others).
'tray' placed inside 'beer' is 'BETRAYER'.
'needs' is the link.
Can you help me to learn more?
(Other definitions for betrayer that I've seen before include "Eg Judas Iscariot" , "snake" , "grass" , "traitor" , "Shopper" .)