stultify

UK/ˈstʌltɪfaɪ/US/ˈstʌltɪfaɪ/

verbC2Very rare — outside the 30,000 commonest English words, so you will meet it in writing rather than in speechformal · an editor’s judgementToo rare in one of the two pools to compare — fewer than 20 uses in speech or in writing

Other forms: stultifying, stultified

To stultify is to dull the mind until it can no longer think or act. Not one blow — years of the same thing.

The adjective stultifying is far commoner than the verb, and stultifying boredom or a stultifying routine describes work that empties somebody out. It is formal and rather literary. There is an older legal sense meaning to make something ineffective, which survives in writing about rules that stultify their own purpose. Deadening is the plainer word for the same effect.