Vinoth "(i thought creating glossary will bring popup) and didnt made any entry."
That's a very strange idea, having an "empty glossary".
Now, the explanation is as follows.
1.- In Site administration ► Plugins ► Filters ► Manage filters you enabled: Activity names auto-linking
2.- Then you created a Glossary and named it "Moodle" (another strange idea!). And you did not enter any definitions in your glossary (strange again...).
3.- In one actitity/resource on your course (in the screenshot example it's a forum discussion), there occurred the word "Moodle". Now, because of your decision in #1 to autolink activity names, and your decision in #2 to name your glossary "Moodle", the word "Moodle", being an activity name in your course, appeared as a link to that glossary activity!
I wish people would read the documentation, and understand what they are doing before in their Moodle courses before asking for help. But, if they did, then there would be almost no work left for the "helpful moodlers".