If you are sure that there is a TD entry for the exact same term in the Term Database, there are 4 possible causes for this behaviour:
1- The term database associated with the project is different than the one where the term is present.
2- The term is present in the term database, but it is not active and approved. This article explains:
In WorldServer, proposed TD entries are not displaying in Browser Workbench3- The term is present and active/approved, but the source and/or target language does not match the one in the project. Note that WorldServer considers different languages also different sorts of the same language. For instance,
Spanish,
Spanish (Mexico), and
Spanish (International) are treated as separate languages. The same applies to
English and
English (United States) and so on. The project's source and target language must match the ones set for the term in the term database.
4- The term is present, but the Term Database is restricted and the user does not have permission to read the TD.