'associationistic' originates from English, specifically formed from the word 'association' plus the suffix '-istic', where 'association' ultimately comes from Latin 'associare'/'associatio' meaning 'to unite, join, or ally', and the suffix '-istic' (from Greek -istikos via Latin) means 'pertaining to a practice, doctrine, or characteristic'.

'associationistic' developed from the noun 'association' (Middle English from Old French/Latin 'associatio', from Latin 'associare'), combined with the adjectival suffix '-istic' (from Greek '-istikos' via Latin '-isticus') to form a modern English adjective meaning 'pertaining to association/associationism'.

Initially the roots referred broadly to 'joining' or 'being united'; over time, when combined as 'associationistic' it came to be used specifically for matters related to the doctrine of associationism (ideas linked by association).