Green’s Dictionary of Slang

humongous adj.

also humangous, humongeous, humongoid, humungous, humungus
[sugg. by SE huge/monstrous/tremendous]

(orig. US) enormous, outsized, huge.

Cosmos (Coe College, Iowa) 5 May 2/4: Maybe at the bottom there will be something worthwhile that us humble sheep, your poor blind, flock, will gather around that humongous soapbox in the sky to listen to.
[US]Current Sl. II:2 18: Humangous, adj. One size larger than manjonious.
[US]Wash. Post 21 Aug. D7/5: [classified advert] Used boats -- humongeous savings on all remaining models!
[US]New Yorker 16 Aug. 26: She uses expressions like ‘the whole megillah’ (meaning the whole long story) and ‘humongous’ (meaning huger than huge and more tremendous than tremendous).
[Can]Totally True Diaries of an Eighties Roller Queen 🌐 14 Aug. I’m going to the recreation center right next door to the high school. It has a whirlpool, humungus pool, six diving boards [...] and an ice rink that’s open in the summer.
[US]C. Hiaasen Skin Tight 256: Not humongous titties but nice pointy ones.
[US]M. Myers et al. Wayne’s World II [film script] garth: My dad would start off with a humungoid bowl of Hormel’s extra spicy chili.
[US]Source Oct. 176: Alongside the humongous and windowless maquila factories.
[UK]Guardian G2 7 Mar. 13: It’s this humongous fishing trip.
[Ire]P. Howard PS, I Scored the Bridesmaids 79: He sees the humungous stack of Valeys on my bed.
[US]Mad mag. Nov. 60: How come you drive such a humogous [sic] gas-guzzling SUV?
[US]C. Hiaasen Star Island (2011) 33: Maury Lykes had invested a humongous sum of money.
[UK]J. Fagan Panopticon (2013) 255: A humongous spliff clamped in her gob.
[US]C. Hiaasen Squeeze Me 54: How often does a person get the chance to see a humongous headless serpent?
[Ire]P Howard Braywatch 233: [A] humungous Montecristo burning between his fingers.