formative
Concise Oxford English Dictionary © 2008 Oxford University Press:
formative/ˈfɔːmətɪv/
▶adjective serving to form something, especially having a profound influence on a person's development.
■ Linguistics denoting or relating to any of the smallest meaningful units that are used to form words in a language, typically combining forms and inflections.
– derivatives
formatively adverb.
formatively adverb.
'formative' also found in these Oxford entries:

