Source : Webster's Revised Unabridged Dictionary (1913)

Senseless \Sense"less\, a.
   Destitute of, deficient in, or contrary to, sense; without
   sensibility or feeling; unconscious; stupid; foolish; unwise;
   unreasonable.

         You blocks, you stones, you worse than senseless
         things.                                  --Shak.

         The ears are senseless that should give us hearing.
                                                  --Shak.

         The senseless grave feels not your pious sorrows.
                                                  --Rowe.

         They were a senseless, stupid race.      --Swift.

         They would repent this their senseless perverseness
         when it would be too late.               --Clarendon.
   --- {Sense"less*ly}, adv. -- {Sense"less*ness}, n.

Source : WordNet®

senselessly
     adv 1: in a meaningless and purposeless manner; "these innocent
            bystanders were senselessly killed"
     2: in an unreasonably senseless manner; "these temples were
        mindlessly destroyed by the Red Guards" [syn: {mindlessly}]