The Collaborative International Dictionary of English v.0.48:
Unretentive \Unretentive\ See retentive.WordNet (r) 3.0 (2006):
unretentive adj 1: (of memory) deficient in retentiveness or range; "a short memory" [syn: unretentive, forgetful, short] [ant: long, recollective, retentive, tenacious]