Synonyms for Substantial:

adj.

all (adjective)
significant, material, real, solid, strong.
generous (adjective)
plenteous, plenitudinous, bounteous.
important (adjective)
extraordinary, principal, fundamental, crucial, valuable, central, vital, serious, key.
important, ample (adjective)
generous, considerable, key, big, plentiful, large, material, solid, firm, abundant, stout, strong, valuable, sturdy, principal, extraordinary, consequential, meaningful, vast, significant, heavy, sound, stable, serious.
material (adjective)
worldly, solid, corporeal, real, tangible, concrete, natural, material, objective, palpable, physical.
material, real (adjective)
physical, objective, concrete, sensible, tangible, corporeal, actual, true, visible, phenomenal.
overweight (adjective)
stout.
real (adjective)
factual, authentic, honest, true, visible, veritable, real, concrete, actual, solid, tangible, genuine, sincere.
rich (adjective)
opulent, well-to-do, affluent.
solid (adjective)
set, solid, stable, firm, hard, physical, concrete, dense.
strong (adjective)
stout.
substantial (adjective)
immanent, considerable, united, physical, actual, solid, real, sturdy, important, meaningful, bodily, significant, substantive, firm, tangible, appreciable, material, palpable.
wealthy (adjective)
rich, opulent, well-to-do, affluent.

n.

high, enormous, extensive, huge, widely. matter, frugal, body, phenomenal, sensible, celebratory, alfresco, slap-up, sit down, light. windfall, megabucks, continue, Payout, wealth, mint, big bucks, fortune, sure, big money, pile, unshakable. bountiful, big, rich, immense, vast, wide, voluminous, plenteous, copious, give, ample, king-size, plentiful, bounteous, plenitudinous, abundant, generous, heavy. monumental, sober, consequential, stolid, large, funereal, officious, deep, humorlessly, solemn, historic, in earnest. stout. principal, valuable, extraordinary. visible. much. opulent, well-to-do, affluent. considerable (noun)
large, abundant, ample, much, plentiful.
substantial (noun)
in essence, essential, real, strong, wholesome, substantive, satisfying, hearty, considerable, solid, sound, material, significant.

Other synonyms:

plenteous, large, extensive, stolid, unshakable, huge, bounteous, widely, plenitudinous, officious. historic, solemn, much, sensible, consequential, sober, phenomenal, bountiful. monumental, copious, plentiful, abundant. ample, voluminous. generous. high, serious. big, deep. weighty
heavy.

Usage examples for substantial

  1. " I'm glad and thankful," said the other, again drawing a breath of relief, " and to show my appreciation of your services, Darby, I shall send you a substantial check." – Red Money by Fergus Hume
  2. His spirit had recognised, had touched, a spirit, which included all that he most needed, and union with which would be the most certain and substantial prize offered by life. – Robert Browning by Edward Dowden