Your question about what is the opposite of true reminded me of when 2 elders were at my door, uninvited askiing me why our family was not attending the meetings anymore and the rehearsed " depressed, tired, work" excuse went out the window and I mentioned the issue I was having with the 2010 change of the word generation.
Of course as I'm sure you an imagine, Proverbs 4:18 was touted and the term "present truth" was mentioned. That was my cue to ask if the current teaching is consider "present truth" what should the previous teaching be called. I said " If its not present, it must be "past",... And if its not "truth" it must be,.........". the elder I was talking to would not say the word that was apparent to everyone and being "lie" ie if its not present truth, it must be past lies"
His mind would not allow him to go there.
NJY