spoonful (n.)

Old English spon "chip, sliver, shaving, splinter of wood," from Proto-Germanic *spe-nu- (source also of Old Norse spann, sponn "chip, splinter," Swedish spån "a wooden spoon," Old Frisian spon, Middle Dutch spaen, Dutch spaan, Old High German span, German Span "chip, splinter"), from PIE *spe- (2) "long, flat piece of wood" (source also of Greek spathe "spade," also possibly Greek sphen "wedge").

As the word for a type of eating utensil, c. 1300 in English (in Old English such a thing might be a metesticca), in this sense supposed to be from Old Norse sponn, which meant "spoon" as well as "chip, tile." The "eating utensil" sense is specific to Middle English and Scandinavian, though Middle Low German spon also meant "wooden spatula." To be born with a silver spoon in one's mouth is from at least 1719 (Goldsmith, 1765, has: "one man is born with a silver spoon in his mouth, and another with a wooden ladle").

word-forming element attached to nouns (and in modern English to verb stems) and meaning "full of, having, characterized by," also "amount or volume contained" (handful, bellyful); from Old English -full, -ful, which is full (adj.) become a suffix by being coalesced with a preceding noun, but originally a separate word. Cognate with German -voll, Old Norse -fullr, Danish -fuld. Most English -ful adjectives at one time or another had both passive ("full of x") and active ("causing x; full of occasion for x") senses.

It is rare in Old English and Middle English, where full was much more commonly attached at the head of a word (for example Old English fulbrecan "to violate," fulslean "to kill outright," fulripod "mature;" Middle English had ful-comen "attain (a state), realize (a truth)," ful-lasting "durability," ful-thriven "complete, perfect," etc.).