Early 18th century; earliest use found in Shaftesbury's Characteristicks. Alteration of didactic, with suffix substitution, perhaps after other adjectives ending in -active.
Definition of didactive in US English:
didactive
adjective
Didactic.
Origin
Early 18th century; earliest use found in Shaftesbury's Characteristicks. Alteration of didactic, with suffix substitution, perhaps after other adjectives ending in -active.