1) Absent-minded 2) Apt to forget 3) Daydreaming 4) Distracted 5) Failing to keep in mind 6) Inattentive 7) Mindless 8) Not mindful or attentive 9) Preoccupied 10) Short 11) Unmindful 12) Unretentive 13) Vague 1) Absentminded 2) Amnesiac 3) Inattentive 4) Neglectful 5) Negligent 6) Senile 7) Unmindful 8) Unretentive 
• (a.) Causing to forget; inducing oblivion; oblivious. • (a.) Heedless; careless; neglectful; inattentive. • (a.) Apt to forget; easily losing remembrance; as, a forgetful man should use helps to strengthen his memory.
For·get'ful adjective 1. Apt to forget; easily losing remembrance; as, a forgetful man should use helps to strengthen his memory. 2. Heedless; careless; neglectful; inattentive. « Be not forgetful to entertain strangers.» Hebrew xiii. 2. 3....
[adj] - failing to keep in mind
oblivious adjective failing to keep in mind; `forgetful of her responsibilities`; `oblivious old age`
apt to forget; that forgets: a forgetful person. · heedless or neglectful (often fol. by of&hasp;): to be forgetful of others. · bringing on oblivion: forgetful slumber.