We already know that verbs can be nouns - these are called Gerunds. Look at this sentence -

Smoking is forbidden.

"Smoking" is the subject, and "is forbidden" is the verb (in the present passive)

Subjects and objects must be nouns, and here "smoking" is the subject. "Smoking" is a gerund and "smoking" is the subject, so the Gerund is a noun. The gerund follows all the normal rules for nouns, but we find it more rarely in the plural. Do you know why? No? H'm .... maybe I can teach you something about nouns! (To find out why gerunds are rarer in the plural, keep reading...., )

but first -

Nouns are often used as adjectives.

For instance, your mouse is probably sliding over a mouse mat. "Mouse" is a noun, but here it is being used as an adjective. Look at these examples -

The History department   /   The Tax office  /  Rain clouds  /  Football boots

Got the idea?   Let's go on.

This is often colloquial, and is also a way or new verbs to enter the language.

Consider the verb "to boycott"

Boycott is an English name. There was once a Mr Boycott who was a member of parliament. When England was having one of its many arguements with the Irish, Mr Boycott suggested that the English should not trade with the Irish. So "to boycott" entered the language, meaning "to refuse to trade or do business with".

Other examples that have entered by the same route are "to ace" and "to blackball" .

Just to make your life harder, English people often make up new ones spontaneously. Someone might say "Let's fish and chips tonight".
(But if they say "Let's breakfast at nine", that's perfectly good English, because "breakfast" is a verb which has become a noun.)

Some nouns refer to a single thing that is composed of a number of individual items. For example - a herd of cows. The herd is a single entity, but the meaning is "a large number of animals". In the same way the government is made up of individual politicians. So we change our verb to show whether we are thinking of the single entity or its components.

For example: "The government has increased taxes." The speaker is talking about the actions of a single part of the state, as shown by the use of the third person present singular with "s". (remember - present perfect is still a present tense!).

But "The government are thieves" shows that the speaker has a very low opinion of individual members of the government.

We always use "the police" as a plural noun. "The police have arrested him." "The police are coming."

Many insubstantive words are concepts - like "happiness", or "imagination" and most concept words (note the noun adjective) are uncountable. Many gerunds are concept words (so they do not have plurals, as uncountable nouns mostly don’t have plurals).

For example "He likes singing."

"Singing" here does not describe a particular song, but the general concept of making music with your mouth. Because this gerund is a general concept, here it is not plain whether our sentence means that the man likes to sing, or that he likes to listen to other people singing, or that he likes both to sing and listen to people singing. That's one of the joys of English - you can be as precise or as vague as you want!

If you don't know what countable and uncountable nouns are, you should look at the intermediate level. (But for those people with bad memories, uncountable nouns are things that you can't have two or more of. "Two happinesses" sounds a little bit strange.

As was mentioned above, uncountable nouns cannot have plurals. But they can - when you are talking about a particular type of uncountable noun.

Look at beer. (Yes, please!) Beer is uncountable. When you tell the barman "two beers, please" this is just a lazy way of saying "two glasses (or bottles) of beer, please". But really, beer is uncountable - like water. But while we say the English drink a lot of beer (beer being uncountable), the English drink many types of beer. For example in my area, Greene King is a popular beer, and in Yorkshire many people drink Tetley's. Both these beers are English beers and they taste different from German beers.

We can also talk about the joys of being a parent, unless children are one of your hates. However, other types of uncountable/insubstantive nouns do not work like this. So we say "there are many types of courage" and not "there are many courages".