What does "shopping" mean?

Shopping is a colloquial term for a raid/attack in Clash of Clans. Generally if they say it's a "nice shopping trip", then they either got a lot of the type of loot they were looking for, or just a lot of loot in general. So in the replay where his defense won, the attacker probably got a decent amount of loot from the attack, and "going shopping" would be attacking some one else for loot.

Note: I have not heard this used by many people, and most of the people I have heard use it are from the UK, so it is possible that it is a regional term to use instead of raiding/looting/farming/attacking.