Is “deep” an adverb in “They dug the well deep.” or something else?

Question

They dug the well deep.

What is "deep" in that sentence? I think its adverb but I stood wrong, help me someone!

Answer 1

You can also understand that sentence like this:

They dug the well (to be | so it was) deep.

in which case deep is a characteristic of the well, not a manner of digging.

Compare:

They ate the fish raw.

P.S. Consider the following. The parentheses around to be indicates that those words could be used in an actual statement but may be omitted without change of meaning.

They wanted the well (to be) deep.

deep is a characteristic of the (intended) well, not of the wanting itself.

So they dug the well (to be) deep.

Transitive dig here is directed (volitional or intentional) action.

Answer 2

If it were an adverb, it would be "deeply". It's an object predicative like in "They painted the town red.", not describing a manner of doing but rather the end state of the sentence object.

Answer 3

What is it exactly that makes you think that you're wrong? You certainly are on the right track with your assertion that it's an adverb. It definitely sounds like one. And one of the biggest reasons why it's an adverb and not any other part of speech has to do with the fact that it answers the following question:

To what degree did they dig the well?

The answer would obviously be "They dug the well deep." or just "Deep." In other words, they dug the well to a great depth. As an adverb of degree, it modifies the verb dug, telling us to what degree the well was dug. It was dug deep.

---

If deep in the OP's example is an adjective modifying the well, as some people here are suggesting with no proof, because according to their logic when you dig a well deep, you end up with a deep well, then, what would happen if the sentence contained no noun phrases at all like this:

Dig deep!

Is deep still an adjective? It can't be an adjective because there is no noun it can possibly modify. The verb to dig seems to work mostly with adverbs (e.g. Try digging deeper. - there is no object, as you can see, which means that deeper is the comparative form of the adverb deep) unlike some other verbs in English such as paint or eat.

Answer 4

TL;DR: It is possible to analyze deep as being an adjective or as an adverb.

WHY

Deep can be either an adjective or an adverb because not all adverbs end in -ly, some are indistinguishable from adjectives. Grammarians call them flat adverbs, so today we can advise someone to “drive safe” or “drive safely”, and to “stay close”. You can say that you “had a bad exam” (adj) or, informally, “did bad at the exam” (adv); however, most careful speakers will consider “did badly at the exam” to be the correct form.

Which Words Are Flat Adverbs?

Here’s a short list: “far,” “fast,” “hard,” “slow,” “quick,” “straight”, “clean,” “close,” “deep,” and “fine”. So go ahead and say, “He kept his cards close” or “Please sit tight.”

Source: Do All Adverbs End in -Ly? By Grammar Girl

While deep can also be an adjective, deeply can never be an adjective.

• “we dug DEEP” (adverb of manner) and “we dug a DEEP hole” (adj)
• “go DEEP in the forest” (adverb of location), and ”went into the DEEP forest” (adj)
• “be DEEPLY moved” (adverb of degree) or “feel a DEEP sadness” (adj)
• but “a deeply forest” (WRONG) or “a deeply hole” (WRONG) are both ungrammatical.

Adverbs answer the following questions: How? When? Where? How often? and Why?

Consider the following examples, all the adverbs answer the question how:

1. They dug the well good = good is usually an adjective but in many American English dialects (if not all) it is also an adverb. Here it can either mean well or completely and thoroughly.
2. They dug the well well = well is an adverb, meaning “in a good or satisfactory way”
3. They dug the well better [this time] = this is the comparative form of the adverb well
4. They dug the well best = the superlative form of the adverb well
5. They dug the well deep = adverb of manner

The adverb well and its derivatives describe the verb dig, they are placed after the object. They express the manner in which the action was performed.

• How did they dig the well?
• They dug it good and deep.

Furthermore, any of the following adverbs, such as slow/slowly, quick/quickly, competently, badly, and shoddily could replace deep, e.g.

• They dug the well slow

Although slow is also an adjective, here it must be an adverb. We don't normally describe wells as being slow.

Furthermore, we can add another adverb to modify ‘deep’

6. They dug the well very deep OR They dug the well very deeply (both are correct)

If we replace deep with an appropriately similar adjective, the sentence is ungrammatical

7. They dug the well very large (NO)

Large is an adjective and as we all know adjectives modify nouns and pronouns.

8. They dug a very large well (YES)