Antonyms of adj retentive

2 of 3 senses of retentive

Sense 1
retentive (vs. unretentive), recollective, long, tenacious -- (good at remembering; "a retentive mind"; "tenacious memory")

unretentive (vs. retentive), forgetful, short -- ((of memory) deficient in retentiveness or range; "a short memory")

Sense 3
retentive -- (having the power, capacity, or quality of retaining water; "soils retentive of moisture")

INDIRECT (VIA impermeable) -> permeable -- (allowing fluids or gases to pass or diffuse through; "permeable membranes"; "rock that is permeable by water")

Similarity of adj retentive

3 senses of retentive

Sense 1
retentive (vs. unretentive), recollective, long, tenacious -- (good at remembering; "a retentive mind"; "tenacious memory")
          Also See-> mindful#1, aware#2

Sense 2
retentive -- (having the capacity to retain something)

Sense 3
retentive -- (having the power, capacity, or quality of retaining water; "soils retentive of moisture")
       => impermeable (vs. permeable) -- (preventing especially liquids to pass or diffuse through; "impermeable stone"; "an impermeable layer of scum"; "a coat impermeable to rain")