There are a couple of places where I get confused on whether a word is an adverb or a preposition (or maybe even both?). For example, a sentence I am confused by is

"Don't throw out the water bottle!"

In this context, some people in my class think that "out" is a preposition, and that "out the water bottle" is the prepositional phrase in the sentence. However, other people think that it is an adverb describing where one is throwing. Similarly, another example is

"Please don't write down my answer!"

Here, is "down" an adverb, or a prepositional phase, and why is it that way? Do these questions have a right/wrong, or is it more like a gray area? Is there a specific logic behind it?

  • 1
    These particles are the linguistic counterpart to Einstein's "spooky action at a distance".
    – TimR
    Aug 8, 2023 at 11:55

4 Answers 4


They are both prepositions.

In the first, out does not form a phrase with the water bottle as it is possible to switch their position:

Don't throw out the water bottle.

Don't throw the water bottle out.

Its function here is a particle - a single word that is allowed in combination with a particular verb. Particles can be verbs, adjectives, or prepositions. These can switch places with the object.

They cut short the seminar. [adjective]

They cut the seminar short.

He let slip a very intriguing detail. [verb]

He let a very intriguing detail slip.

She wrote down the answer. [preposition]

She wrote the answer down.

Their category is irrelevant from the point of view of modification or complementation as they cannot take (or are at least extremely limited in their range of) dependents when functioning as a particle.

Still, there is no reason to reassign these words to the adverb category simply because they are functioning as a direct dependent of a verb - complements in this case, not modifiers, as they are only allowed by a very specific subset of verbs.

This is similar to nouns acting as dependents in noun phrases and not being reassigned to the adjective category. Few would argue that school in the sentence below is an adjective.

We got on the school bus.

In general, down and out are best analyzed as prepositions as they are able to modify nouns regardless of whether they are used by themselves or with dependents. This is something most will agree adverbs cannot do.

[The hike out] wasn't long.

[The view out the side ports] spoke volumes.

[The way down] was lit with candles.

I'm just going to buy [the house down the block].

  • I prefer to see such particles as a separate class; they are far removed from the prototypical prepositions. CGEL correctly rejects FANBOYS on such grounds. Aug 10, 2023 at 18:22
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    @EdwinAshworth "Particle" is a grammatical relation like "subject" or "object." CGEL spends so much time talking about particles because they aren't all prepositions. Some are adjectives and some are adverbs (the ones that behave like adverbs! Not the ones that behave like prepositions). Aug 10, 2023 at 21:30
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    @EdwinAshworth That Wiki article is a car crash unfortunately. And not one reference where it would count. But the main reason for my comment is that DW makes it clear that's how they're using the word, by stating that "it's function here is particle" and "when functioning as a particle" etc, etc and also by contrasting them with modifiers and DOs. But yes, some writers (generally those who cannot keep their PoS and functions separate in the first place) class particles from phrasal verbs as a PoS. Granted. Aug 12, 2023 at 14:44
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    @Araucaria-Nothereanymore. Interesting article indeed! A significant caveat to a general test delimiting prepositions and adverbs. Can always double check using the sole complement in a complex-intrasitive headed by be test: The lights were out / *The lights were brokenly. Still, even per the article, adverbs are limited and rather rare as modifiers in NPs, whereas prepositions (with objects or not) are extremely common.
    – DW256
    Aug 13, 2023 at 3:43
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    @EdwinAshworth On the contrary! The preposition class is alive and well. In fact, now that it is clear that an NP object is not a requirement for membership, prepositions have been better distinguished from other classes, eliminating the need for multiple part of speech entries in dictionaries and increasing the accuracy of corpus searches where an adverb wildcard should no longer return prepositions!
    – DW256
    Aug 13, 2023 at 4:02

Some people call them prepositions, and other people call them adverbs, and a significant number of people give them yet a different name: particles. But only if they undergo Particle Shift:

  • Throw the water bottle out! ~ Throw out the water bottle! (OK either side of NP object)
  • Throw it out!, but not *Throw out it! (Only OK after pronoun object)

Here's the list of particles that undergo the rule:

  • up/down, in/out, on/off, over/under, through, by, past, to, about, across, along, around, behind

There are also a few other words that are hard to call prepositions because they never head a PP: back, forth, away, apart, aside, together. These also undergo the rule:

  • Throw away the bottle/Throw the bottle away/Throw it away, but not *Throw away it.

And here are the undoubted prepositions:
aboard, above, after, against, amid, among, anent, at, atop, before, below, beneath, beside, between, beyond, but, circa, concerning, despite, during, except, for, from, inside, into, notwithstanding, of, onto, opposite, outside, pending, per, save, since, till, toward(s), underneath, until, unto, upon, via, with, within, without, etc.

All these are bad in the frame: V NP __

  • *I nailed the lamp above
  • *We threw marshmallows at
  • *I washed the car before
  • *You should leave the car between

As to what you wanna call them, suit yourself. Nobody cares (except teachers, if you're still in school) because such grammatical terms are always arbitrary and represent the prejudices of the grammarian using them. Hence as long as you're consistent, you can use any term you like.

  • Came [right back]. [Back [from the edge]]. She's [back home]. <--- They're PP's, though. Aug 10, 2023 at 21:36
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    How about took it inside / put it underneath / kept it within? And I've washed the car before seems okish to me too. Fiddly, these small words, aren't they. Aug 12, 2023 at 14:44

Out is a preposition in prepositional phrases like

  • throw out the widow (the window is the prepositional object of out)
  • ran out the door
  • ran down the hill

But out is an adverb or what some grammarians call a prepositional adverb in sentences similar to yours:

  • throw out the bottle (the bottle is the direct object of the VP throw out, NOT the prepositional object of out)
  • carried out the job
  • write down the answer

Thought.co quotes The Elements of English Grammar by George Philip Krapp, who explains

The difference between the pure preposition and the prepositional adverb is illustrated by the following two sentences:

  • He ran up the stairs.
  • He ran up a bill.

In the first sentence, a prepositional phrase, stairs is the object of up. The expression up the stairs is a prepositional phrase modifying the verb ran. In the second sentence, however, bill is not the object of up and up a bill is, therefore, not a prepositional phrase modifying the verb ran.

Rather, the word up is acting as a prepositional adverb modifying the verb ran. Together, the two words form the phrasal verb ran up, an expression whose distinct meaning has nothing to do with the act of running (Krapp 1970).

  • 1
    There's something inelegant about these Frankenstein categories that conflate parts of speech with labels for function in clause structure. Also note the lack of reasoning: the labels are just applied as though it's clear to everyone why it must be so.
    – DW256
    Aug 8, 2023 at 14:28
  • Throw out the widow? Why what did she do? And even if it's a typo for window who typically throws out windows? Please, can you come up with something more natural-sounding?
    – Mari-Lou A
    Aug 10, 2023 at 15:19
  • Crystal came up with the term 'lexeme' for 'strings behaving as a single word' (as well as to cover {throw, throws ...}), and many of the multi-word verbs in this category have single-word synonyms ('carry out' = 'perform / execute'; 'throw out' = 'discard'; 'write down' = 'inscribe / record / notate' ...). I tend to see 'run up' [a bill] as a unary transitive MWV; if 'up' here needs a name, I just use 'particle in a MWV'. Aug 10, 2023 at 18:29
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    How can "The elements of English grammar, by Krapp" not be a satirical spoof? Aug 10, 2023 at 21:42

Lots and none at all.

"Out" is prepositional, not adverbial, but "out the water bottle" is a misunderstanding, not a phrase.

If they're to be separated then "out" belongs not with the bottle but necessarily with "throw."

It might in some odd circumstance be possible to use "The bottle out…" as an answer to "What was thrown?" but those circumstances would pretty-much be limited to discussions of grammar and syntax, not to actual speech.

I suggest you'll find more help on Question like this in English Language Learning

  • 2
    I think a question about words that are particles functioning as complement of a verb in a transitive clause is better suited to ELU than ELL.
    – BillJ
    Oct 17, 2021 at 7:02
  • @BillJ On a level using that language, I'd agree… only, Kong wasn't. Oct 17, 2021 at 21:34

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