From cartoon + -ish.
cartoonish (comparative more cartoonish, superlative most cartoonish)
- Exaggerated or caricatured, in the manner of a cartoon
- Synonyms: cartoonesque, cartoony
- She was grinning a big, cartoonish grin.
2012 August 21, Jason Heller, “The Darkness: Hot Cakes (Music Review)”, in The Onion AV Club:
Since first tossing its cartoonish, good-time cock-rock to the masses in the early ’00s, The Darkness has always fallen back on this defense: The band is a joke, but hey, it’s a good joke. With Hot Cakes—the group’s third album, and first since reforming last year—the laughter has died. In its place is the sad wheeze of the last surviving party balloon slowly, listlessly deflating.