Este exercício está mal feito.

Because este is a demonstrative adjective: it goes directly before a noun.

• este exercício = this exercise
• isto = this / this thing and is used without a noun

So you can say:

• Este exercício está mal feito.
• Isto está mal feito.

But not isto exercício.

In European Portuguese, the basic distinction is:

• este = this, near the speaker
• esse = that, near the listener or something already mentioned
• aquele = that over there, farther from both

So este exercício usually means this exercise here / the one I’m referring to now.

This distinction is often taught more clearly in European Portuguese than in everyday Brazilian Portuguese, where usage can be looser.

Because estar is commonly used to describe the state or result of something.

• está mal feito = it is in a badly done state / it has been done badly

Here the speaker is commenting on the result of the exercise as completed.

If you said é mal feito, it would sound more like a general characteristic, as if something is inherently badly made or poorly constructed. For an exercise correction, está mal feito is the natural choice.

This is a very common question.

• mal is usually an adverb = badly
• mau is an adjective = bad

In mal feito, mal modifies feito, so it means badly done.

Compare:

• um mau exercício = a bad exercise
• um exercício mal feito = an exercise done badly

A useful shortcut:

• mal often contrasts with bem
• mau often contrasts with bom

Feito is the past participle of the verb fazer (to do / to make).

• fazer → feito

It is irregular, so it does not follow a regular pattern like -ado or -ido.

In this sentence, feito works like done in English:

• mal feito = done badly

Because feito agrees with exercício, which is masculine singular.

• este exercício → masculine singular
• therefore: feito

If the noun were feminine singular, you would use feita:

• Esta ficha está mal feita.

And in the plural:

• Estes exercícios estão mal feitos.
• Estas fichas estão mal feitas.

Yes. Both are possible, but they focus on slightly different things.

• Está mal feito → focuses on the current result/state
• Foi mal feito → focuses more on the action in the past: it was done badly

In a teacher’s correction, está mal feito is very natural because the teacher is looking at the exercise as it now exists.

Because mal feito is the normal, natural order in Portuguese for this idea.

Here mal modifies the participle feito, and the combination mal feito is a very common expression meaning badly done.

While Portuguese word order can sometimes vary, feito mal would sound unnatural in this sentence.

So the standard form is:

• está mal feito

In this sentence, write it as two words: mal feito.

That is because mal is functioning as an adverb meaning badly, modifying feito.

You may sometimes come across malfeito as a lexicalized adjective in some contexts, but for the meaning in this sentence, mal feito is the standard and safest choice.

A rough European Portuguese pronunciation would be something like:

ESHT(uh) ez-er-SEE-syu shtah mahl FAI-tu

A few useful points:

• este often sounds like esht(e), with the final vowel very weak
• exercício is stressed on cí
• está in connected speech often sounds close to shtá
• final -o in European Portuguese often sounds like u

So feito sounds roughly like FAI-tu, not FAY-toh.

The accent shows where the stress falls:

• e-xer-CÍ-cio

Portuguese spelling uses accent marks to show stress and sometimes vowel quality. In exercício, the stress is on cí, which is why the accent is written.

For learners, the important thing is: do not stress the first syllable. The strong syllable is CÍ.

It can cover several negative ideas depending on context:

• done incorrectly
• done carelessly
• poorly structured
• not done according to instructions

So está mal feito is broader than just one answer is wrong. It often suggests the work as a whole was not done properly.

If you only want to say that an answer is incorrect, Portuguese might use more specific wording, such as está errado for it is wrong. Here, mal feito suggests poor execution.