WordNet sense 1 (not marked by the use of reason):

mindless, reasonless

WordNet sense 2 (not reasonable; not showing good judgment):

unreasonable

WordNet sense 3 (lacking import):

pointless, purposeless

WordNet sense 4 (having no meaning or direction or purpose):

nonmeaningful

WordNet sense 5 (unresponsive to stimulation):

insensible

WordNet sense 6 (not conscious; lacking awareness and the capacity for sensory perception as if asleep or dead):

unconscious

WordNet sense 7 (lacking or marked by lack of intellectual acuity):

stupid

WordNet sense 8 ((of especially persons) lacking sense or understanding or judgment):

witless, nitwitted, soft-witted