"Isn't it time you stopped acting the goat"- Is this correct grammatically?

Question

Another question from Tintin's Flight 714. At a particular time, Professor Calculus started acting very foolishly in front of some respectable people. So, Captain Haddock, Calculus's friend, whispered into the professors' ears:

Isn't it time you stopped acting the goat?

I read it in my mind as:

Isn't it the time you stopped acting like the goat?

I admit, during speaking, people can forget the "the" and "like" (although I wouldn't have forgotten adding the "like"), but using "the" before "goat" seems a blunt grammatical mistake. I think it should be "a" instead of "the". It could have been "the" if Haddock was comparing the Homo sapiens (human) species with the Capra aegagrus hircus species. But he was comparing a human from the human species with just a goat from the goat species. So it should be "a" instead of "the". How come then Haddock used "the" instead of "a"? Or is it just a simple error while speaking?

Answer 1

Question one: isn't it time, or isn't it the time?

We always say it's time, not it's the time:

It's time.
It's time I went home.
It's time for you to go to bed.
It's time you started eating right.
It's time for some fun!

We can turn all of these into questions:

Isn't it time?
Isn't it time I went home?
Isn't it time for you to go to bed?
Isn't it time you started eating right?
Isn't it time for some fun?

And yours fits this second pattern:

Isn't it time you stopped acting the goat?

It would be unidiomatic if you inserted the. People might not understand you.

In fact, the article is never used with this sense of the word, which is "the appointed, due, or proper time" (from the OED). Why not? To be honest, I have no idea. As far as I know, it's simply a matter of idiom.

---

Question two: acting the goat, or acting like the goat?

This is an English idiom, and you can find it in dictionaries:

to behave in a silly way, sometimes in order to make people laugh Insecure and lonely, he resorted to acting the goat to get people's attention.

You're right that acting would normally be followed by like today. But it's not ungrammatical to say it without like, and I suppose when this idiom was formed, it may have been more common to use act this way. But in any case, since it's an idiom, you shouldn't change it by inserting like.

Why do I say it's grammatical? Well, you can act silly, which shows us that act is a verb like be, become, or grow. Since it can take an adjective, we can tell these verbs take "predicative complements" (PCs) rather than objects, like most verbs. (We can tell this because objects can't be adjectives.) So just as you can say being the goat, you can say acting the goat.

---

Question three: the goat, or a goat?

Again, it's an idiom, so you shouldn't change it. Otherwise people won't understand!

But why the? Presumably it's the same reason we say playing the fool. We're not talking about any actual fool, nor any actual goat. We're referring to the qualities of a generic or archetypical fool or goat.

(Though, to be honest, I have no idea what makes that goat-like. It's a pretty weird idiom!)

---

Notes

Note one: the subordinate clause you stopped acting the goat is in the past tense, but it doesn't indicate past time. Instead, it indicates counterfactuality. In The Cambridge Grammar of the English Language, this use of the past tense is called the modal preterite.

Note two: Play the goat is a fairly unusual idiom. It was chosen, I think, to translate the original French idiom faire le zouave, which is fairly silly.

Answer 2

I'm going to disagree with @snailboat's answer a bit in regard to the question of the presence/absence of like.

If you check the dictionary definitions of act, starting at definition 19 you'll find a section marked as "Verb (used with object)". Unlike "act [adjective]" (like act silly), this specifically addresses "act [noun]" (like act Macbeth or act the goat).

In fact, definition 19 specifically is the one we want:

to represent (a fictitious or historical character) with one's person: to act Macbeth.

In this sense it is synonymous with play or portray.