co·los·sal 
(kə-lŏsəl)
(kə-lŏsəl)adj.
1. Of great size, extent, or amount; immense. See Synonyms at enormous.
2. Of great scope or consequence; monumental: a colossal blunder.
[French, from Latin colossus, colossus; see COLOSSUS.]
co·lossal·ly adv.