"Phase shift varies with frequency and can advance or retard as the frequency changes" I looked up Webster's American English Thesaurus and the antonym for 'advance' in the sense that it's used in your sentence is recede. Here is the same sentence rewritten using recede. "Phase shift varies with frequency and can advance or recede as the frequency changes." This is an easy case where you could have used correct langu…
In this context? I'll agree that recede might be a better choice in this case, but as an undergrad in physics I hear the word retard being used in similar contexts all the time in the sense of slowing down. It crops up especially often in classical mechanics problems.