Rashi on Genesis
חרפה הוא THAT WERE A DISGRACE — Amongst us it is somewhat of a blot on our pedigree, for if one wishes to revile another, he says to him: “You are an uncircumcised person”, or “the son of an uncircumcised person”. The word חרפה always means “reviling”.
Sforno on Genesis
כי חרפה היא לנו, it would appear that none of the circumcised men among us were fit to marry our sister.
Radak on Genesis
ויאמרו ...כי חרפה היא לנו, to be intermarried with the uncircumcised, seeing that our males are all circumcised.