* "render": This word can be used to mean "to give up" or "to make something available", which is close to the meaning of surrender. It is also pronounced very similarly.
* "rend": This word means "to tear or split" and while not directly related to surrender, it can be used figuratively to suggest a forceful taking away, which is a kind of surrendering.
It's important to note that neither of these are perfect homonyms, but they do share some similarities in pronunciation and meaning that make them suitable for use in certain contexts.