Il giradischi resta traballante.

Yes, -i often marks a masculine plural, so this can look confusing at first.

But giradischi is a compound noun. It comes from elements meaning something like disk-turner / record-turner, and its form is fixed. That means the singular and plural are the same:

• il giradischi = the record player / turntable
• i giradischi = the record players / turntables

So here, il tells you it is singular.

Italian usually uses an article with a singular countable noun when talking about a specific thing.

So:

• Il giradischi = the turntable / record player

In English, we sometimes omit articles more easily, but Italian generally does not. Saying just giradischi on its own would sound incomplete in a normal sentence unless it were, for example, a label or a heading.

Yes, in this sentence it is masculine singular, and you can tell because it takes il:

• il giradischi

If it were feminine, you would expect an article like la instead.

Because giradischi is an invariable compound noun, the noun ending itself is not very helpful here, so the article is the clearest clue.

Resta is the third-person singular present of restare, meaning to remain or to stay.

So resta traballante suggests:

• it continues to be wobbly
• it remains wobbly, perhaps even after something changed or after someone checked it

If you said:

• Il giradischi è traballante

that would simply mean The turntable is wobbly.

So resta adds the idea of continuing in that condition.

Yes. Resta traballante and rimane traballante are very close in meaning.

Both can mean remains wobbly. In many contexts, they are interchangeable.

Very roughly:

• resta = remains, stays
• rimane = remains

In this sentence, both sound natural. A learner should mainly understand that both verbs express continuation of a state, unlike a simple è.

Traballante is an adjective. It means something like:

• wobbly
• shaky
• unstable
• rickety

In this sentence, it describes the condition of il giradischi.

Because it comes after a linking-type verb like restare, it functions as a predicate adjective, not as an adjective directly placed before the noun.

It actually does agree with the noun, but this adjective has a form that can be deceptive.

Traballante is one of those adjectives in -ante that have:

• singular: traballante
• plural: traballanti

In the singular, the masculine and feminine are the same:

• il giradischi traballante
• la sedia traballante

But in the plural, both become:

• i giradischi traballanti
• le sedie traballanti

So here traballante matches a singular noun.

No. It can be used both literally and figuratively.

Literal examples:

• un tavolo traballante = a wobbly table
• una sedia traballante = a shaky chair

Figurative examples:

• un accordo traballante = a shaky agreement
• una situazione traballante = an unstable situation

In Il giradischi resta traballante, the meaning is most naturally physical.

The sentence has a very common structure:

• Il giradischi = subject
• resta = verb
• traballante = adjective describing the subject’s state

So the pattern is:

subject + linking/state verb + adjective

This is similar to English structures like:

• The table remains unstable
• The machine stays noisy

Usually, with this kind of meaning, you would most naturally place it after the noun:

• il giradischi traballante

In your sentence, it comes after resta, which is also normal:

• Il giradischi resta traballante

Putting it before the noun, as in il traballante giradischi, is possible only in special stylistic contexts, but it sounds much less neutral and much less common.

A simple approximate guide:

• giradischi ≈ jee-ra-DEE-skee
• resta ≈ RES-ta
• traballante ≈ tra-bal-LAN-te

A few useful pronunciation notes:

• gi before i sounds like the j in jam
• schi sounds like skee
• the stress in traballante falls on -lan-

So the full sentence sounds roughly like:

eel jee-ra-DEE-skee RES-ta tra-bal-LAN-te

Here is the present tense:

• io resto = I remain / stay
• tu resti = you remain / stay
• lui / lei resta = he / she remains
• noi restiamo = we remain
• voi restate = you all remain
• loro restano = they remain

So in your sentence, resta agrees with il giradischi, which is third-person singular.