What is "substantival"

Substantival \Sub`stan*ti"val\, a. Of or pertaining to a substantive; of the nature of substantive. -- Sub`stan*ti"val*ly, adv.

a. (context grammar English) Of or pertaining to a substantive.

adj. of or relating to or having the nature or function of a substantive (i.e. a noun or noun equivalent); "a substantival constitutent"