What is an antonym for replied?

There isn't a single perfect antonym for "replied" because the word has a few nuances depending on context. Here are some options:

For "replied" meaning "answered a question or comment":

* Ignored

* Disregarded

* Overlooked

* Avoided

* Dismissed

For "replied" meaning "responded in a conversation":

* Remained silent

* Said nothing

* Didn't respond

* Staid quiet

For "replied" meaning "said something back":

* Remained silent

* Said nothing

* Didn't speak

The best antonym will depend on the specific context of your sentence.