Word by Word Analysis

وَإِذَا بَدَّلْنَآ ءَايَةً مَّكَانَ ءَايَةٍ ۙ وَٱللَّهُ أَعْلَمُ بِمَا يُنَزِّلُ قَالُوٓا۟ إِنَّمَآ أَنتَ مُفْتَرٍۭ ۚ بَلْ أَكْثَرُهُمْ لَا يَعْلَمُونَ 101

And when We substitute a verse in place of a verse - and Allāh is most knowing of what He sends down - they say, "You, [O Muḥammad], are but an inventor [of lies]." But most of them do not know.