n.
Function: noun
Date: 1586
1 a : an unevenness of surface (as of the ground in lawn bowling) b : OBSTRUCTION , DIFFICULTY <the rub is that so few of the scholars have any sense of this truth themselves ― Benjamin Farrington> c : something grating to the feelings (as a gibe or harsh criticism) d : something that mars serenity
2 : the application of friction with pressure <an alcohol rub >