Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
retentive is an adjective meaning "good at remembering". It carries 3 recorded senses.
good at remembering
“a retentive mind”
“tenacious memory”
having the capacity to retain something
having the power, capacity, or quality of retaining water
“soils retentive of moisture”
Definitions, synonyms and semantic relations for retentive come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.