chock-full (adj.)

"either of the two fleshy sides of the face below the eyes," Old English ceace, cece "jaw, jawbone," in late Old English also "the fleshy wall of the mouth," of uncertain origin, from Proto-Germanic *kaukon (source also of Middle Low German kake "jaw, jawbone," Middle Dutch kake "jaw," Dutch kaak), not found outside West Germanic, probably a substratum word.

Words for "cheek," "jaw," and "chin" tend to run together in IE languages (compare PIE *genw-, source of Greek genus "jaw, cheek," geneion "chin," and English chin); Aristotle considered the chin as the front of the "jaws" and the cheeks as the back of them. The other Old English word for "cheek" was ceafl (see jowl (n.1)).

A thousand men he [Samson] slow eek with his hond, And had no wepen but an asses cheek. [Chaucer, "Monk's Tale"]

In reference to the buttocks from c. 1600. Sense of "brazen insolence" is from 1840, perhaps from a notion akin to that which led to jaw "insolent speech," mouth off, etc. To turn the other cheek is an allusion to Matthew v.39 and Luke vi.29. Cheek-by-jowl "with cheeks close together," hence "in intimate contact" is from 1570s; earlier in same sense was cheek-by-cheek (early 14c.). In ballroom dancing, cheek-to-cheek is from 1919 (earlier it was a measurement of apples). 

1560s, "violent encounter of armed forces or a pair of warriors," a military term, from French choc "violent attack," from Old French choquer "strike against," probably from Frankish, from a Proto-Germanic imitative base (compare Middle Dutch schokken "to push, jolt," Old High German scoc "jolt, swing").

Meaning "a sudden blow" is from 1610s; meaning "a sudden and disturbing impression on the mind" is from 1705. Sense of "feeling of being (mentally) shocked" is from 1876. Medical sense is attested from 1804 (it also once meant "seizure, stroke," 1794). Shock-absorber is attested from 1906 (short form shocks attested by 1961); shock wave is from 1907. Shock troops (1917) translates German stoßtruppen and preserves the word's original military sense. Shock therapy is from 1917; shock treatment from 1938.