Menu bar application icon (Razer Synapse) remains even after uninstalling the app. (Solved)

Hold command and space to open spot light. then type: Uninstall Razer Synapse

You should find a application named Uninstall Razer Synapse in the suggestion. run it and unstall the razer synapse.

p.s: What is the actual case was, even though we removed the synapse app by putting it into the trash, it was not removed entirely.