Having the quality or power to form, shape, or give expression; serving to form or fashion.
From efform + -ative suffix. A rare adjective describing the capacity or tendency to give form, used in philosophical contexts to discuss creative and generative principles.
You'd think 'formative' (as in 'formative years') would derive from 'efformative,' but they have independent histories—'efformative' stayed in specialized philosophy while 'formative' became everyday English.
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