Use ‘zypper addlock’. For example, remove ‘showfoto’, then do
# zypper al showfoto
Specified lock has been successfully added.
When an attempt is made to install it again it will be prevented unless lock is removed…
# zypper in showfoto
Loading repository data...
Reading installed packages...
Resolving package dependencies...
Problem: conflicting requests
Solution 1: remove lock to allow installation of showfoto-5.5.0-2.11.x86_64[repo-oss]
Solution 2: do not ask to install a solvable providing showfoto.x86_64 = 5.5.0-2.11
Choose from above solutions by number or cancel [1/2/c] (c):