substitute

American  

[suhb-sti-toot, -tyoot] / ˈsʌb stɪˌtut, -ˌtyut /

noun

1. a person or thing acting or serving in place of another.

   Synonyms:

   equivalent, replacement, alternative

2. (formerly) a person who, for payment, served in an army or navy in the place of a conscript.

3. Grammar. a word that functions as a replacement for any member of a class of words or constructions, as do in He doesn't know but I do.

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verb (used with object)

substituted, substituting

1. to put (a person or thing) in the place of another.

2. to take the place of; replace.

3. Chemistry. to replace (one or more elements or groups in a compound) by other elements or groups.

verb (used without object)

substituted, substituting

1. to act as a substitute.

adjective

1. of or relating to a substitute or substitutes.

2. composed of substitutes.

substitute British  

/ ˈsʌbstɪˌtjuːt /

verb

1. (often foll by for) to serve or cause to serve in place of another person or thing

2. chem to replace (an atom or group in a molecule) with (another atom or group)

3. logic maths to replace (one expression) by (another) in the context of a third, as replacing x + y for x in 3 x = k gives 3 x + 3 y = k

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noun

1. 1. a person or thing that serves in place of another, such as a player in a game who takes the place of an injured colleague

   2. Often shortened to: sub.  ( as modifier )

      a substitute goalkeeper

2. grammar another name for pro-form

3. another name for supply teacher

4. nautical another word for repeater

5. (formerly) a person paid to replace another due for military service

Usage

What does substitute mean? A substitute is someone or something that takes the place of another person or thing. As a verb, to substitute means to make such a switch. Substitute is used in a variety of contexts, but it is perhaps most commonly associated with substitute teachers and players in team sports who replace a player in the game. In both cases, the word is often shortened as sub. Example: Mr. Jones was sick today so we had a substitute.

Other Word Forms

• intersubstitutability
  noun
• intersubstitutable
  adjective
• intersubstitution
  noun
• nonsubstituted
  adjective
• nonsubstitution
  noun
• nonsubstitutional
  adjective
• nonsubstitutionally
  adverb
• nonsubstitutionary
  adjective
• presubstitute
  verb (used with object)
• presubstitution
  noun
• prosubstitution
  adjective
• substitutability
  noun
• substitutable
  adjective
• substituter
  noun
• substitutingly
  adverb
• substitution
  noun
• substitutional
  adjective
• substitutionally
  adverb
• substitutionary
  adjective
• unsubstituted
  adjective

Etymology

Origin of substitute

First recorded in 1350–1400; Middle English, from Latin substitūtus “replaced,” past participle of substituere “to put in place of,” from sub- sub- + -stituere, combining form of statuere “to set up, erect” ( see substituent)

Explanation

Something or someone that takes the place of another is said to be a substitute. You may be sent into a game as a substitute for an injured player, or you might substitute chocolate chips for blueberries in a pancake recipe. Substitute can be used as an adjective to describe something or someone that takes the place of another. Teenagers are notoriously hard on substitute teachers, sometimes giving them fake names or wrong information about classroom work. Substitute can also be used as a verb. So if you are asked to substitute for a teacher, you probably shouldn't believe everything the students tell you!

Example Sentences

At around $4 to $4.50, shoppers start making substitute purchases.

From MarketWatch • May 17, 2026

"These unjustifiable measures cannot substitute dialogue, nor can pressure replace diplomacy."

From Barron's • May 15, 2026

Sullivan, who became the youngest ever MLS player two years ago, was a first-half substitute and scored in the 75th minute.

From BBC • May 14, 2026

“No matter how sophisticated AI gets,” says the Rev. Justin Bolger, Catholic chaplain for Brown University, “it will never be a substitute for another person, especially God.”

From The Wall Street Journal • May 14, 2026

That is, it didn’t substitute each letter with another letter.

From "The Woman All Spies Fear" by Amy Butler Greenfield

Related Words

• backup
• replacement
• stand-in
• surrogate