We think of mobility as the ease in which electrons or holes can move through a semiconductor lattice, given the electric field. While in some ways, you could confuse resistivity and mobility, mobility is in the units of centimeters squared per volts times seconds. It’s a measure of distance, how far can that electron or hole move in a certain amount of time with a certain amount of voltage across it.
At low fields, carrier drift velocity is proportional to the electric field - this proportionality is the mobility. Conceptually, holes are localized to move through the covalent bond structure, but electrons are free to move about the crystal. Thus, one might expect hole mobility to be less than electron mobility.
Microelectronic Circuit Design, 4th Edition by Richard C. Jaeger & Travis N. Blalock