1. A method comprising: receiving a query for software source code, wherein the query comprises one or more queried domain concept names, wherein at least one of the one or more queried domain concept names is indicated as prohibited; processing the query, wherein the processing comprises: expanding the query to include one or more query terms with relationships to the one or more queried domain concept names based on an ontology, wherein at least one of the one or more query terms is indicated as prohibited at least based on at least one of the relationships to the one or more queried domain concept names, the at least one of the relationships being with the at least one of the one or more domain concept names indicated as prohibited; based on the relationships to the one or more queried domain concept names based on the ontology, assigning weights to the one or more query terms; if two domain concept names of the one or more queried domain concept names are indicated as both prohibited and required due to the expansion, the domain concept name with the greater weight is favored; if the two domain concept names have equal weights, the domain concept name indicated as prohibited is favored; finding where, within the software source code, one or more source code element names mapped to the one or more queried domain concept names appear; and displaying results of the query.
8. The method of claim 1 wherein: the processing avoids finding source code units in which source code elements mapped to the at least one of the one or more domain concept names indicated as prohibited appear.