Steps to  block someone on the Tinder app by unmatching from them:

• Open the Tinder app on your phone.
• Tap the speech bubble in the top right corner to go to your discussions.
• Tap on the person you want to unmatch with in the conversation.
• Tap the shield icon in the top right corner of the screen.
• Tap 'Unmatch' in the 'Safety Toolkit' pop-up menu to disconnect your profiles and prevent the Tinder user from seeing or contacting you.
• Confirm your action by tapping 'yes, unmatch' on the second pop-up.