The noun exhaust refers to what comes out of your car's tailpipe. It consists of the burned gases and particulate matter that are created by the engine. As a verb, the word exhaust means to use something up, such as a food supply or your energy.

The exhaust system in your car is the part that takes the waste created by the car in the form of gas or smoke and expels it through the tailpipe. The noun exhaust appeared in the 19th century, after the invention of the engine. Before that, the word, as a verb, referred only to depleting something, such as a natural resource. Miners deplete a mineral deposit and exhaust the resource.

Definitions of exhaust
  1. verb
    wear out completely
    “This kind of work exhausts me”
    synonyms: beat, tucker, tucker out, wash up
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    exhaust physically or emotionally
    exhaust by allowing to pull on the line
    tire out completely
    type of:
    fag, fag out, fatigue, jade, outwear, tire, tire out, wear, wear down, wear out, wear upon, weary
    exhaust or get tired through overuse or great strain or stress
  2. verb
    use up (resources or materials)
    “We exhausted our savings”
    synonyms: consume, deplete, eat, eat up, run through, use up, wipe out
    occupy, take, use up
    require (time or space)
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    run out
    exhaust the supply of
    deplete of resources
    indulge, luxuriate
    enjoy to excess
    burn, burn off, burn up
    use up (energy)
    spend completely
    play out, run down, sap, tire
    indulge (one's appetite) to satiety
    spend more than available of (a budget)
    spend less than the whole of (a budget, for example)
    type of:
    drop, expend, spend
    pay out
  3. verb
    use up the whole supply of
    “We have exhausted the food supplies”
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    type of:
    make void or empty of contents
  4. verb
    exhaust one's savings”
    synonyms: play out, run down, sap, tire
    play out
    become spent or exhausted
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    type of:
    consume, deplete, eat, eat up, run through, use up, wipe out
    use up (resources or materials)
  5. noun
    gases ejected from an engine as waste products
    synonyms: exhaust fumes, fumes
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    type of:
    waste, waste material, waste matter, waste product
    any materials unused and rejected as worthless or unwanted
    a fluid in the gaseous state having neither independent shape nor volume and being able to expand indefinitely
  6. noun
    system consisting of the parts of an engine through which burned gases or steam are discharged
    synonyms: exhaust system
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    type of:
    instrumentality that combines interrelated interacting artifacts designed to work as a coherent entity
  7. verb
    eliminate (a substance)
    “combustion products are exhausted in the engine”
    synonyms: discharge, eject, expel, release
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    cough out, cough up, expectorate, spit out, spit up
    discharge (phlegm or sputum) from the lungs and out of the mouth
    free of obstruction by blowing air through
    terminate a pregnancy by undergoing an abortion
    produce and discharge eggs
    egest, eliminate, excrete, pass
    eliminate from the body
    bleed, hemorrhage, shed blood
    lose blood from one's body
    eruct, spew, spew out
    eject or send out in large quantities, also metaphorical
    fester, maturate, suppurate
    ripen and generate pus
    breathe, emit, pass off
    expel (gases or odors)
    belch, bubble, burp, eruct
    expel gas from the stomach
    force out
    emit or cause to move with force of effort
    emanate, exhale, give forth
    give out (breath or an odor)
    exhale abruptly, as when one has a chest cold or congestion
    suffer a miscarriage
    flow, menstruate
    undergo menstruation
    perspire, sudate, sweat
    excrete perspiration through the pores in the skin
    exudate, exude, ooze, ooze out, transude
    release (a liquid) in drops or small quantities
    pass after the manner of urine
    empty, evacuate, void
    excrete or discharge from the body
    ca-ca, crap, defecate, make, stool, take a crap
    have a bowel movement
    ptyalise, ptyalize, spew, spit, spue
    expel or eject (saliva or phlegm or sputum) from the mouth
    spit out, splutter, sputter
    spit up in an explosive manner
    send out real or metaphoric rays
    form, produce, or emit bubbles
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