Line has become one of the most popular instant messaging and social networking app on mobile devices. While using Line for instant messaging and voice calls has its own benefits, you might find an annoying or undesirable person in your contacts whom you want to block from your friends list.
Like most instant messaging apps, Naver's Line app also has the feature which enables you to block a friend you don't wish to receive messages and calls from. Just follow this guide and you would be able to easily block any person from calling you and sending you messages.
Tap on Friends on the top menu bar, then tap on Edit at the top left.
In the Edit Friends List screen, tap on the friend you want to block. Tap on the Block button at the bottom.
Tap on the OK button to block the selected user.
In future, if you want to unblock someone, you can see the guide on how to Unblock someone in Line Messenger on Android.