Synonyms for Big:

adj.

all (adjective)
heavy, large.
arrogant (adjective)
bragging, proud, boastful, presumptuous, pretentious, pompous, imperious.
boastful (adjective)
pretentious, self-aggrandizing.
burly (adjective)
hulky.
enthusiastic (adjective)
eager, motivated, fervent, born-again, wholehearted, mad about something, enthusiastic, keen, avid, hooked.
generous (adjective)
liberal, princely, heroic, magnanimous, openhanded, unselfish, bighearted, Great-hearted, lofty.
grown (adjective)
elder, mature, full-grown, adult.
important (adjective)
super, popular, serious, vital, significant, influential, fundamental, prominent, crucial, momentous, consequential, material, meaningful.
large (adjective)
enormous, towering, giant, baggy, vast, comprehensive, soaring, ample, grand, large, prodigious, gargantuan, capacious, magnificent, expansive, great, lofty, grandiose, huge, mammoth, roomy, immense, generous, gigantic, cavernous, sizable, impressive, massive, spacious, humongous, extensive, tremendous, majestic, princely, colossal, awesome, voluminous, elephantine, copious, bulky.
large, great (adjective)
copious, massive, gigantic, ample, voluminous, tremendous, brimming, roomy, oversize, jumbo, awash, substantial, mammoth, hulking, prodigious, vast, whopping, walloping, spacious, colossal, sizable, immense, capacious, enormous, extensive, fat, huge, bulky, humongous.
loud (adjective)
deafening, roaring.
overweight (adjective)
fat, stout.
pregnant (adjective)
parturient.
size (adjective)
high, portly, long, broad, chunky, sizable, amplitudinous, measurable, expansive, large, corpulent, wide, dimensional, voluminous, great, bulky, magnificent, extensive.
successful (adjective)
distinguished, top-rated, brilliant, thriving, triumphant, successful, high-flying.

n.

widely. elder, acclaimed, viral, grown up, top-rated, well-received, popular, much loved/respected/admired/criticized etc.. brisk, brick-and-mortar, ostentatiously, anticompetitive, business, pompously, collective, business-to-business, bloated, accredited, all-night. boo-boo, healthy, choo-choo, good, bow-wow, cold, bunny, tidy, birdie, bang, cross. brotherhood, br, developed, youth, brotherly, conjoined twin, full-fledged, fraternal twin, brother, BRO, ripe, half-brother, full-blown, half sister. parturient, Expecting, reproduction, pregnant, gone. brimful, rich, overflowing, brimming, awash. historic, substantial, meaningful, material, consequential. unselfish, big-hearted, Large-hearted, Great-hearted, give. big (noun)
deep, bigger, boastfully, super, vainglorious, puffy, colossal, conspicuous, oversized, freehanded, liberal, extensive, sizable, grownup, loud, epic, of import, cock-a-hoop, large, titanic, whopping, hulky, grown, life-size, king-size, queen-size, significant, full-grown, jumbo, galactic, braggy, elephantine, heavy, bouffant, giant, monolithic, fully grown, braggart, bountiful, heroic, outsized, enlarged, self-aggrandising, monstrous, larger, thumping, volumed, bragging, walloping, momentous, humongous, larger-than-life, large-scale, greatest, whacking, massive, handsome, immense, biggest, outsize, ample, full-size, giving, macro, wide-ranging, proud, man-sized, largish, oversize, stupendous, banner, extended, monumental, largest, double, gargantuan, boastful, capacious, vauntingly, life-sized, cosmic, overlarge, great, rangy, sizeable, swelled, blown-up, lifesize, gigantic, adult, bulky, hulking, obvious, broad, spacious, plumping, self-aggrandizing, mammoth, wide, biggish, enormous, generous, mature, astronomic, tremendous, vast, mountainous, voluminous, bounteous, important, crowing, queen-sized, prominent, bad, king-sized, astronomical, huge, intense, bighearted, too large, prodigious, openhanded, magnanimous.
fat (noun)
buxom, obese, fat, overweight, plump, stout, chubby, tubby.
pompous (noun)
imperious, pretentious, presumptuous, pompous, egotistic.
with child (noun)
Expecting, parturient, pregnant.

Other synonyms:

brother, cold. gone. cross. bang. considerable
good.
fat
chubby, tubby, plump, obese, buxom.
Other relevant words:
conspicuous, astronomical, grown, prominent, developed, distinguished, full-blown, momentous, consequential, important, full-grown, adult, pretentious, mature, tidy, bighearted, ripe, loud, substantial, full-fledged, astronomic, magnanimous, heavy.

Usage examples for big

  1. You are like a big boy more than a man! – One Maid's Mischief by George Manville Fenn
  2. It's such a great big work. – A College Girl by Mrs. George de Horne Vaizey
  3. Ah, I tell you, he is to be a big man. – The Joyous Adventures of Aristide Pujol by William J. Locke