The most common and most likely answer to this crossword clue is the 6 letter word E-SHOP
I've seen this crossword clue in The Guardian
E
-
S
H
O
P
More clues leading to the result E-SHOP
Buddy explains!
The straight part
We know that "retailer" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case retailer = e-shop.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does E-SHOP mean?
E-SHOP noun- A sales outlet which supplies goods or services over the Internet.