Other forms: saps, sapped, sapping
Sap is the liquid that carries water and food through a tree or plant. Sticky sap, the sap rises, sap on the windscreen.
It rises in spring, which gives the phrase the sap is rising, used of trees and, jokingly, of people. Maple syrup and rubber are both made from sap. As a verb, to sap means to weaken something gradually: sapped his strength, saps morale — which comes from a quite different word, an old military term for undermining a wall. Note sapling, a young tree, and sappy, which in America means over-sentimental.
1nounsapThe liquid carrying water and food through a plant.
“The sap runs for about six weeks in early spring.”
2verbweakenTo weaken something gradually.
“Two years of it sapped every bit of his enthusiasm.”
sap is a plant liquid, or a weakening.
Old English saep is Germanic and unrelated to the verb. The verb sap comes from Italian zappa, a spade, by way of siege warfare — digging under a wall to bring it down, which is why a sapper is a military engineer.
Middle English
sap
English, today
sap
Built from
From Middle English sap. From Middle English sap, from Old English sæp (“juice, sap”), from Proto-West Germanic sap (“sap, juice”) (compare Dutch sap, German Saft, Icelandic safi), from Proto-Indo-European sab-, sap- (“to taste”) (compare Welsh sybwydd (“fir”), Latin sapa (“must, new wine”), Russian со́пли (“snivel”), xcl համ (“taste”), ae 𐬬𐬌𐬱𐬁𐬞𐬀 (“having poisonous juices”), Sanskrit सबर् (“juice, nectar”)). More at sage. sap (“naive person”) is a clipping of sapskull literally “person with sap in their skull”.
Etymology from Wiktionary, CC BY-SA