When we call a person or an animal marauding, we mean they are moving about from place to place looking for something to attack, steal, smash, or kill. It is not a quiet walk. A marauding gang might go through streets at night breaking things and taking what they want. A marauding lion is one that has left its usual ground and is going after cattle — or even people. You meet this word more in news stories, history books, and wildlife writing than in everyday chat; it sounds a little serious and a little old-fashioned, in a useful way. People also stretch it. A newspaper might talk about marauding fans after a football match even when nobody is trying to kill anyone: they just mean the group is roaming around and making trouble. The verb behind it is maraud; a person who does this is a marauder. In ordinary talk many people would simply say raiders, or a gang on the loose, and keep marauding for writing.