Adjectives

(a)large, bigabove average in size or number or quantity or magnitude or extent“a large city”, “set out for the big city”, “a large sum”, “a big (or large) barn”, “a large family”, “big businesses”, “a big expenditure”, “a large number of newspapers”, “a big group of scientists”, “large areas of the world”
(s)bigsignificant“graduation was a big day in his life”
(s)bad, bigserious or severe“a bad headache”, “in a big rage”, “had a big (or bad) shock”, “a bad earthquake”, “a bad storm”
(s)bigloud and firm“a big voice”, “big bold piano sounds”
(s)big, large, prominentconspicuous in position or importance“a big figure in the movement”, “big man on campus”, “he's very large in financial circles”, “a prominent citizen”
(s)big, heavyprodigious“big spender”, “big eater”, “heavy investor”
(s)big, swelled, vaingloriousfeeling self-importance“too big for his britches”, “had a swelled head”, “he was swelled with pride”
(s)adult, big, full-grown, fully grown, grown, grownup(of animals) fully developed“an adult animal”, “a grown woman”
(s)bigmarked by intense physical force“a big wind”
(s)big, large, magnanimousgenerous and understanding and tolerant“a heart big enough to hold no grudges”, “that's very big of you to be so forgiving”, “a large and generous spirit”, “a large heart”, “magnanimous toward his enemies”
(s)big, bighearted, bounteous, bountiful, freehanded, handsome, giving, liberal, openhandedgiven or giving freely“was a big tipper”, “the bounteous goodness of God”, “bountiful compliments”, “a freehanded host”, “a handsome allowance”, “Saturday's child is loving and giving”, “a liberal backer of the arts”, “a munificent gift”, “her fond and openhanded grandfather”
(s)big, enceinte, expectant, gravid, great, large, heavy, with childin an advanced stage of pregnancy“was big with child”, “was great with child”

Adverbs

(r)bigextremely well“his performance went over big”
(r)boastfully, vauntingly, big, largein a boastful manner“he talked big all evening”
(r)bigon a grand scale“think big”
(r)bigin a major way“the play failed big at the box office”