- unretentive, forgetful - not retentive
- unmindful, forgetful, mindless - not mindful or attentive; "while thus unmindful of his steps he stumbled"- G.B.Shaw
- forgetful, oblivious - failing to keep in mind; "forgetful of her responsibilities"; "oblivious old age"
Antonym: attentive (indirect, via inattentive)