adj. [ p. pr. of verb deaden{ 3 }. ] Rendering less lively, intense, or vigorous; as, the deadening effect of some routine tasks. [ WordNet 1.5 ]

2. So lacking in interest as to cause mental weariness; as, the deadening effect of some routine tasks.
Syn. -- boring, dreary, ho-hum, irksome, tedious, tiresome, wearisome. [ WordNet 1.5 ]

n. The act of making something futile and useless (as by routine).
Syn. -- stultification, impairment. [ WordNet 1.5 ]