Quick Info

The Conflicts field lists packages that are in conflict with this package. This means both packages cannot both be installed simultaneously on the same system. This is important for packages that include similar or very closely related tools or files. Note that if two packages offer the exact same tool (i.e. say /usr/bin/sendmail) then they are in conflict just because of that (because you cannot install a package that overwrites files from another.) However, the command line to install two packages in conflict is --force-conflicts, whereas, allowing two packages that have a file in common is --force-overwrite. It is therefore a good idea to add all conflicts you know about.

The Conflict field is a list of packages as defined in the Depends field.

You may also want to check out the Breaks field.