Is that bad ??Panic not, it may be nothing of the sort.
But if it is it depends on the size of the lurcher and the severity and cause of the problem it can however be fixed sometimes by doing nothing or if needed with a operation that is usually successful. Would be an idea to ask your vet to check knees and if they are ok the hips.
However it is possible to hear clicking and it be impossible to find anything wrong so don't panic just yet.