exhaust

Formsexhausts, exhausting, exhausted

Pluralexhausts (some meanings)

1. 1
   verbtransitive

   To use something up completely, so that the supply or stock of it comes to an end.

   Planners warn that the city could exhaust its water reserves within a decade.

   By midnight the search team had exhausted every possible lead.

   Similardeplete, consume, expend, drain

   Oppositereplenish

   Note

   Supplies of anything can be exhausted, literal or not: resources, reserves, patience, a grandfather's stock of bad jokes. With possibilities, options and leads the meaning shifts slightly, since to exhaust all possibilities is to try each one until none is left untried. You're exhausting my patience uses this sense; you're exhausting me belongs to the tiring meaning, though the irritation behind both is much the same.

2. 2
   verbtransitive

   To tire someone out completely, wearing them down until they have no energy left.

   Back-to-back night shifts exhaust even the youngest nurses on the ward.

   The steep climb exhausted the hikers, so they rested for an hour at the ridge.

   Similartire, fatigue, drain, weary

   Oppositerefresh, invigorate, energize, revive

   Note

   The two participles split the work the way boring and bored do: an exhausting day is the cause, an exhausted runner the one worn out. The passive takes by, and writers lend it to things that cannot tire: H. P. White, writing in 1960 on the Hawkhurst branch, has the line climb into the Wealden hills until, apparently exhausted by the effort, it stops short of the village.

3. 3
   noununcountable

   Waste gas given off by an engine as it burns fuel.

   Diesel exhaust hung over the loading dock all morning.

   During rush hour, idling trucks fill the downtown streets with exhaust.

   Similarfumes

4. 4
   nouncountable

   The set of engine parts through which burned gases or steam are carried away and released.

   A leak anywhere in the exhaust can let fumes seep into the cabin.

   The locomotive's exhaust was rebuilt to carry spent steam away from the cylinders more freely.

   Note

   The bare noun covers three things that the full compounds keep apart: the exhaust system as a whole, the exhaust pipe at its end, and the exhaust gas flowing through both. A leak in the exhaust usually means the system; a chrome exhaust means the pipe you can see; choking on exhaust means the gas itself. When precision matters, the compound says which.

5. 5
   nouncountable

   The pipe through which waste gases leave an engine, especially on a motor vehicle.

   His motorcycle has a chrome exhaust that sweeps up past the rear wheel.

   A loose exhaust was dragging along the road behind the pickup, throwing sparks.

   Similartailpipe

6. 6
   verbtransitive

   To draw off or let out the whole of something, such as water or moisture, draining it away completely.

   Engineers needed two large pumps to exhaust the floodwater from the mine.

   Hot, dry winds exhaust the moisture from the topsoil within days.

   Similardrain

   Note

   The Latin picture survives almost unchanged here: exhaurīre joins ex, "out", to haurīre, "to draw water, drain". Water is exhausted out of a well, moisture is exhausted from the earth by evaporation, and the object is always the thing drawn off. The tiring and using-up meanings grow from the same idea of drawing something away until none is left.

7. 7
   verbtransitive

   To empty a container or space by drawing off or letting out its contents.

   Technicians exhaust the test chamber of air before each run begins.

   The divers waited while the ballast tank was exhausted and refilled with seawater.

   Similarempty, evacuate, drain

   Oppositefill

   Note

   Here the verb turns round and takes the container as its object: one exhausts a well, a tank, a test chamber, and the contents, when named, follow of, as in exhausting the tank of air before filling it with water. Beside the drawing-off sense, only the end of the operation the sentence names has changed. Exhausting a treasury already leans toward the using-up meaning.

8. 8
   verbtransitive

   To discuss a topic thoroughly and completely, leaving nothing more to be said about it.

   By the third hour the committee had exhausted the topic and turned to the budget.

   Few historians manage to exhaust a subject as large as the Civil War in a single book.

9. 9
   verbtransitive

   To expel used air or gas from a space or machine as exhaust.

   Many hospital wards exhaust stale air outdoors instead of recirculating it.

   The factory exhausts its fumes through a tall stack behind the plant.

   Similarexpel, vent, discharge

   Note

   Ventilation talk sets it against recirculate: exhausted air leaves for good after a single use instead of going round again, a choice Michael Phiri and Bing Chen tie to fewer infections. The object is whatever is pushed out, stale air or fumes. Compare the intransitive engine use, which needs no object at all.

10. 10
    verbintransitive

    To discharge spent gas or steam, or to escape as exhaust, typically through a pipe, port or vent.

    Both cylinders exhaust into a shared pipe that leads up to the stack.

    When the valve shifts, the line exhausts through the side port and the pressure drops.

    Similarvent, discharge

    Note

    Engineering prose lets either the gas or the part be the subject. Steam exhausts through receiver pipes in The Railway and Engineering Review of 1910, and in Alan Darbyshire and Charles Gibson's Mechanical Engineering (2022) a valve output exhausts through the exhaust port, verb and noun side by side. It travels with a preposition of route, through or into, because the point is where the spent pressure goes.

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