This tutorial will show how to delete a WhatsApp contact on iPhone. There is no way to delete a contact from within WhatsApp.
Step #1 – You must delete the contact from your iPhone’s Contacts app
Step #2 – In your iPhone’s Contacts app tap on the name of the contact
Step #3 – Tap Edit in the top right corner.
Step #4 - Scroll all the way to the bottom.
Step #5 – Tap Delete Contact.