How we differentiate between compound noun and adjective? in the following examples I couldn't identify them.

  • promising result(s)
  • washing machine.

Note: I know "washing machine" is compound noun because it is known as one item.

in the same context, How we differentiate between gerund (Part of a compound noun) and present participle (Adjective)?

  • A Central Australian soil mapping study has shown promising results.
  • He don't have washing machine.
  • 1
    What's the point of "differentiating" them? As an intellectual exercise, perhaps it can be amusing, but does this in any way enhance communication? If you just want to know the grammar, this might be a better question for EL&U.
    – Andrew
    Commented Mar 1, 2017 at 20:23
  • If I could know it is compound noun I can easily use adjectives with it, if it is not I don't think i can, So, I can apply the nouns rules on compound nouns and so on
    – Shannak
    Commented Mar 1, 2017 at 20:28
  • 1
    I see what you mean. I don't think there are any rules other than vocabulary, though. "Washing" isn't an adjective, but I only know this because I've memorized the word.
    – Andrew
    Commented Mar 1, 2017 at 20:43

2 Answers 2


The main difference between "promising" in "promising result" and "washing" in "washing machine" is that "promising" is only an adjective that has hardly any verbal force or meaning. In general, -ing forms used as adjectives like surprising, interesting, boring, breathtaking, amusing, etc. do have a verbal meaning ("an interesting book" is a book that interests the reader), but that is not the case with "promising".

In "washing machine" -- which is a compound noun -- "washing" can be interpreted as a gerund (a machine for washing), or as a present participle (a machine that washes). The same test may be followed with most compound nouns of this kind: in "walking stick", "walking" is a gerund (nominal) because the noun can be understood as "a stick for walking" (NOT a stick that walks), and the same applies to swimming pool, but more often than not the -ing form in compound nouns can be interpreted either as a gerund (nominal) or as a present participle (adjectival), as in "washing machine" or "cleaning products" (products for cleaning, or products that clean).


washing machine

is a compound noun and you can treat it like any other noun, add adjectives

big red wishing machine

or make plural

big red washing machines

  • Thanks, but how we can differentiate between compound noun and adjective when see them?
    – Shannak
    Commented Mar 1, 2017 at 20:50
  • For starters, look at whether the first word is actually an adjective. "washing" is a verb, not an adjective. So "washing machine" simply cannot be an adjective-noun combination (though I'm sure there are exceptions, this is English after all). Past that, it's not easy to differentiate. Many of the words that are now compound nouns started out as adjective-noun combinations.
    – Peyton B
    Commented Mar 1, 2017 at 23:21

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