adj

• Of the essence or essential element of a thing.
  "Substantive editing is never trivial, whereas some aspects of copyediting are trivial."
• (law) Applying to essential legal principles and rules of right.
  "substantive law"
• (chemistry, of a dye) Not needing the use of a mordant to be made fast to that which is being dyed.
• (grammar) Of or pertaining to a substantive.

noun

• (grammar) Ellipsis of noun substantive or substantive noun, a noun or a group of words (a noun phrase) that act as a noun (in a sentence).
  "The Dutch verb beelden and substantive beelding signify form-giving, creation, and by extension image—as do gestalten and Gestaltung in German, where Neo-Plastic[ism] is translated as Die neue Gestaltung."

verb

• (grammar, very rare) To make a word belonging to another part of speech into a substantive (that is, a noun) or use it as a noun.