retentive
re-ten-tive
adjective
Having the ability to remember facts and experiences easily and for a long time.
"She possesses a remarkably retentive memory."
adjective
Able to hold or keep a substance within itself, preventing its escape.
"Clay soil is very retentive of water."
Thesaurus
Synonyms: tenacious, recollective, long, impermeable
Antonyms: forgetful, short, unretentive