If Bob Smith says, "Kevin is . . .", and I only hear "Kevin is", did I ignore the ". . ."? According to the dictionary, my not hearing this part is not ignoring it, if a loud noise prevented me from hearing it. According to the dictionary, it would only consider my having ignored it if I actively rejected the words in the ellipses. Personally, I would use the word in every case, but maybe that is just me.
I would define ignore as every single word I did not hear, and it would not matter why I did not hear it. If I treat ignore this way, will I confuse the listener?