1) Amnesiac 2) Asinine 3) Daffy 4) Fatuous 5) Foolish 6) Forgetful 7) Inane 8) Meaningless 9) Nonintellectual 10) Nonmeaningful 11) Reasonless 12) Rote 13) Senseless 14) Silly 15) Unmindful 16) Unquestioning 17) Unreasonable 18) Unretentive 19) Vacuous 1) Devoid of intelligence 2) Intellectually unstimulating 3) Meaningless 4) Nonmeaningful 5) Nonthinking 6) Not mindful or attentive 7) Stupid 8) Vacuous 
• (a.) Not indued with mind or intellectual powers; stupid; unthinking. • (a.) Unmindful; inattentive; heedless; careless.
Mind'less adjective 1. Not indued with mind or intellectual powers; stupid; unthinking. 2. Unmindful; inattentive; heedless; careless. « Cursed Athens, mindless of thy worth.» Shak. 
[adj] - not marked by the use of reason 2. [adj] - lacking the thinking capacity characteristic of a conscious being 3. [adj] - requiring little mental effort
reasonless adjective not marked by the use of reason; `mindless violence`; `reasonless hostility`; `a senseless act`