Both Uses of

fatuous

in

Light in August

But on Sunday evening, and with the echo of the phantom hooves still crashing soundlessly in the duskfilled study, he watches quietly the puny, unhorsed figure moving with that precarious and meretricious cleverness of animals balanced on their hinder legs; that cleverness of which the man animal is so fatuously proud and which constantly betrays him by means of natural laws like gravity and ice, and by the very extraneous objects which he has himself invented, like motor cars and furniture in the dark, and the very refuse of his own eating left upon floor or pavement; and he thinks quietly how right the ancients were in making the horse an attribute an†
Chpt 3

He did not even have to be told in words that he had surely found the lost Lucas Burch; it seemed to him now that only crassest fatuousness and imbecility should have kept unaware.†
Chpt 4 *

Definition:

without intelligence -- often implying a smugness or complacency