the act of making something futile and useless (as by routine)
source: WordNet 3.0
so lacking in interest as to cause mental weariness
A boring evening with uninteresting people. The deadening effect of some routine tasks. A dull play. His competent but dull performance. A ho-hum speaker who couldn't capture their attention. What an irksome task the writing of long letters is. Tedious days on the train. The tiresome chirping of a cricket. Other people's dreams are dreadfully wear.