adjective

extremely large or great.

a colossal amount of mail

huge,massive,enormous,gigantic,very big,very large,great,giant,mammoth,vast,cosmic,immense,tremendous,mighty,stupendous,monumental,epic,prodigious,mountainous,monstrous,titanic,towering,elephantine,king-sized,king-size,gargantuan,Herculean,Brobdingnagian,substantial,extensive,hefty,bulky,weighty,heavy,gross,mega,monster,whopping,whopping great,thumping,thumping great,humongous,jumbo,hulking,bumper,astronomical,astronomic,whacking,whacking great,ginormous