tagger

The word "tagger" usually refers to a person, tool, or program that puts a tag, label, or mark on something. In everyday use, one of its most common meanings is a graffiti writer: someone who leaves a stylized name, symbol, or quick design on walls, trains, signs, or other surfaces. These marks may be seen as vandalism, art, or both, depending on the setting and the viewer.

But the word is broader than graffiti. A "tagger" can also be someone who adds keywords or labels to organize information. For example, a person might tag photos on social media, label files in a computer system, or add subject words to articles, books, or images so they are easier to find later. In technical fields, a tagger can even be a software tool, such as a program that automatically labels words or data.

There are also older or simpler uses. In the game of tag, the person who is "it" may be called the tagger because they are the one trying to touch the other players. In all of these cases, the central idea stays the same: a tagger is the one that adds the tag or mark. The context tells you whether the word points to a graffiti writer, a person labeling information, or a tool that does the job automatically.