sap

¹ American  

[sap] / sæp /

noun

1. the juice or vital circulating fluid of a plant, especially of a woody plant.

2. any vital body fluid.

3. energy; vitality.

4. sapwood.

5. Slang. a fool; sucker; dupe.

6. Metallurgy. soft metal at the core of a bar of blister steel.

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verb (used with object)

sapped, sapping

1. to drain the sap from.

sap ² American  

[sap] / sæp /

noun

1. Fortification. a deep, narrow trench constructed so as to form an approach to a besieged place or an enemy's position.

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verb (used with object)

sapped, sapping

1. to undermine; gradually or insidiously weaken or destroy.

   Synonyms:

   undermine, weaken, tire, impair, exhaust, enfeeble, enervate, drain, deplete

2. Fortification.

   1. to approach (a besieged place or an enemy position) by means of deep, narrow trenches protected by gabions or parapets.

   2. to dig such trenches in (ground).

verb (used without object)

sapped, sapping

1. Fortification. to dig a sap.

sap ³ American  

[sap] / sæp /

noun

1. a short club with a heavy tip that is used as a weapon; blackjack; bludgeon.

   The burglar carried a set of lockpicks and a sap.

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verb (used with object)

1. to hit (someone) with a club.

   If he tries to sneak out, I'll sap him over the head.

SAP ¹ British  

abbreviation

1. South African Police

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SAP ² British  

/ sæp /

acronym

1. Standard Assessment Procedure, the recognized performance indicator for measuring energy efficiency in buildings

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sap ³ British  

/ sæp /

noun

1. a deep and narrow trench used to approach or undermine an enemy position, esp in siege warfare

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verb

1. to undermine (a fortification, etc) by digging saps

2. (tr) to weaken

sap ⁴ British  

/ sæp /

noun

1. a solution of mineral salts, sugars, etc, that circulates in a plant

2. any vital body fluid

3. energy; vigour

4. slang a gullible or foolish person

5. another name for sapwood

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verb

1. to drain of sap

sap Scientific  

/ săp /

1. The watery fluid that circulates through a plant that has vascular tissues. Sap moving up the xylem carries water and minerals, while sap moving down the phloem carries water and food.

2. See cell sap

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Other Word Forms

• sapless adjective

Etymology

Origin of sap¹

First recorded before 900; Middle English; Old English sæp; cognate with Dutch sap; akin to German Saft juice, Old Norse safi; sap ¹ in def. 5 a shortening of saphead

Origin of sap²

First recorded in 1585–95; from French noun sape “spade, spadework,” derivative of saper “to dig a trench,” from Italian zappare “to undermine,” a military term, based on zappa “hoe”

Origin of sap³

First recorded in 1895–1900; perhaps shortening of sapling or sapwood (used as a tool or weapon)

Explanation

To sap something is to drain or deplete something over time. If you sap a maple tree, you drain the liquid inside it to make maple syrup. But if you sap a person of strength, you've rendered him defenseless. Whether used as a noun or verb, sap is rarely a good thing. If your energy or will is sapped, it’s not meant lightly; it means you have been exhausted of all your reserve energy, you’re reduced to a shell. If someone calls you "a sap," it suggests you lack strength and character. And if you get sap — the sticky liquid inside a tree — on your hands, good luck getting it off in the middle of a forest without a bar of soap and running water. Yuck.

Example Sentences

Advancements that seek to end the friction of reality — the freak occurrences, edge cases and bum luck of a given day — ultimately sap the world of excitement and color.

From Salon • Apr. 13, 2026

This could sap a key source of demand for stocks, according to Steve Blitz, chief U.S. economist at TSLombard, who highlighted this risk in commentary shared with MarketWatch on Thursday.

From MarketWatch • Apr. 9, 2026

I think they’re doing so not only because they’re personally disgusted, but because they agree with Judge McKeown that this behavior will eventually sap their authority as a court.

From Slate • Mar. 13, 2026

“A much bigger unwind remains the risk for global equity markets as higher energy prices dampen growth prospects, while higher longer-dated interest rates sap the net present value earnings of the growth stocks,” he added.

From Barron's • Mar. 9, 2026

The fire must be hot enough to keep the sap boiling, but not hot enough to make it boil over.

From "Little House in the Big Woods" by Laura Ingalls Wilder

Related Words

• blunt
• deplete
• destroy
• drain
• erode
• exhaust
• impair
• ruin
• undermine
• vitiate
• wreck