1 of 4

noun (1)

: the fluid part of a plant
specifically : a watery solution that circulates through a plant's vascular system
: a body fluid (such as blood) essential to life, health, or vigor
: bodily health and vigor
: a foolish gullible person
[probably short for sapling] : blackjack, bludgeon
sapless adjective
saplessness noun


2 of 4

verb (1)

sapped; sapping

transitive verb

: to drain or deprive of sap
: to knock out with a sap


3 of 4

verb (2)

sapped; sapping

intransitive verb

: to proceed by digging a sap

transitive verb

: to subvert by digging or eroding the substratum or foundation : undermine
: to gradually diminish the supply or intensity of
sapped her strength
: to weaken or exhaust the energy or vitality of
the illness sapped him of his stamina
: to operate against or pierce by a sap


4 of 4

noun (2)

: the extension of a trench to a point beneath an enemy's fortifications
Choose the Right Synonym for sap

weaken, enfeeble, debilitate, undermine, sap, cripple, disable mean to lose or cause to lose strength or vigor.

weaken may imply loss of physical strength, health, soundness, or stability or of quality, intensity, or effective power.

a disease that weakens the body's defenses

enfeeble implies a condition of marked weakness and helplessness.

enfeebled by starvation

debilitate suggests a less marked or more temporary impairment of strength or vitality.

the debilitating effects of surgery

undermine and sap suggest a weakening by something working surreptitiously and insidiously.

a poor diet undermines your health
drugs had sapped his ability to think

cripple implies causing a serious loss of functioning power through damaging or removing an essential part or element.

crippled by arthritis

disable suggests bringing about impairment or limitation in a physical or mental ability.

disabled by an injury sustained at work

Word History


Noun (1)

Middle English, from Old English sæp; akin to Old High German saf sap

Verb (2)

Middle French sapper, from Old Italian zappare, from zappa hoe

Noun (2)

French sape, from saper

First Known Use

Noun (1)

before the 12th century, in the meaning defined at sense 1a

Verb (1)

1725, in the meaning defined at sense 1

Verb (2)

1598, in the meaning defined at intransitive sense

Noun (2)

1642, in the meaning defined above

Time Traveler
The first known use of sap was before the 12th century

Dictionary Entries Near sap

Cite this Entry

“Sap.” Dictionary, Merriam-Webster, Accessed 4 Feb. 2023.

Kids Definition


1 of 2 noun
: the fluid part of a plant
especially : a watery solution that circulates through a higher plant and carries food and nutrients
: bodily health and vigor : vitality sense 3b
: a foolish person who is easily tricked or cheated


2 of 2 verb
sapped; sapping
: undermine sense 2
heavy waves sapped the seawall
: to weaken gradually
illness sapped my strength

Medical Definition

More from Merriam-Webster on sap

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

The Great British Vocabulary Quiz

  • union jack speech bubble
  • Named after Sir Robert Peel, what are British police called?
True or False

Test your knowledge - and maybe learn something along the way.

Solve today's spelling word game by finding as many words as you can with using just 7 letters. Longer words score more points.

Can you make 12 words with 7 letters?