to misunderstand;  to misconceive;  to misapprehend;  to misjudge;  to mistake;  to misinterpret;  to get somebody wrong
misapprehension;  misunderstanding
I say it again/repeat it so there's no misunderstanding
I think they are at cross-purposes
The statement of the minister is open to misunderstanding
It's through a mere misunderstanding that they bombard each other with insults
To clear up a misunderstanding