Of an action, occurrence, state of affairs, etc.: resulting from lack of sense or intelligence; stupid, foolish; often implying also lack of meaning…

That numbs, or induces numbness.

so cold as to cause numbness.

Stunning, benumbing, paralysing. Obsolete.

That benumbs or renders torpid; paralyzing.

Deadening.

transitive. To deaden. Only found in participles beˈdeaded adj. deadened. beˈdeading n. deadening.

Causing torpor; producing numbness; paralysing; also figurative stupefying, deadening. †torporific eel, the gymnotus or electric eel (obsolete).

Having a dulling or deadening effect.

That deadens: see the verb.