Adjective substantial has 5 senses
  1. significant, substantial - fairly large; "won by a substantial margin"
    Antonym: inconsiderable (indirect, via considerable)
  2. substantial, substantive, in essence - being the essence or essential element of a thing; "substantial equivalents"; "substantive information"
    Antonyms: inessential, unessential (indirect, via essential)
  3. substantial, real, material - having substance or capable of being treated as fact; not imaginary; "the substantial world"; "a mere dream, neither substantial nor practical"; "most ponderous and substantial things"- Shakespeare
    Antonyms: insubstantial, unsubstantial, unreal, aeriform, aerial, airy, aery, ethereal, paper, shadowy, wraithlike
  4. hearty, satisfying, solid, substantial - providing abundant nourishment; "a hearty meal"; "good solid food"; "ate a substantial breakfast"
    Antonym: unwholesome (indirect, via wholesome)
  5. solid, strong, substantial - of good quality and condition; solidly built; "a solid foundation"; "several substantial timber buildings"
    Antonym: unsound (indirect, via sound)