- (grammar) Not having the form of a noun.
- Not having any material substance.
- 2006, Walter Reinhart Tschinkel, The Fire Ants, page 103:
- Nests are formed by the removal of soil to create an unsubstantive space.
- (by extension) Not having any factual substance.
- 2009 January 16, Nicholas Watt and Patrick Wintour, “To deliver a low-carbon economy you have got to have a vision”, in The Guardian:
- Labour dismisses Cameron's interest in the environment as a cynical and unsubstantive part of his attempt to decontaminate the Tory brand.