No facis trampes.

Because Catalan uses the present subjunctive for the negative imperative.

So with the verb fer:

• Fes trampes. = affirmative command to tu
• No facis trampes. = negative command to tu

This is a very common pattern in Catalan:

• Parla → No parlis
• Menja → No mengis
• Fes → No facis

So No fes trampes is not correct standard Catalan.

It comes from the irregular verb fer, which means to do or to make.

Facis is the present subjunctive, 2nd person singular form, used here because the sentence is a negative command addressed to tu.

A few useful forms of fer are:

• fas = you do
• fes = do!
• facis = that you do / used in don’t do

So in No facis trampes, facis literally means something like you do, but in the structure of a negative command it means don’t do.

It is addressed to tu, the informal singular you.

So No facis trampes is what you say to:

• one friend
• one child
• one classmate
• one person you speak to informally

If you wanted other versions, you would say:

• No faci trampes = to vostè
• No feu trampes = to vosaltres
• No facin trampes = to vostès

Because fer trampes is the normal Catalan expression for to cheat.

Even though English often uses a different structure, Catalan normally says fer trampes in the plural. It is best learned as a set expression.

So:

• fer trampes = to cheat
• No facis trampes = don’t cheat

A learner should usually treat fer trampes as one chunk of language rather than translating word by word.

Because in this expression Catalan normally says fer trampes, not fer les trampes.

Many verb + noun expressions in Catalan work without an article when they describe a general activity or behavior. Here, trampes is part of the fixed expression meaning cheating.

So:

• fer trampes = to cheat
• not normally fer les trampes in this meaning

If you added an article, it would usually sound like you were talking about some specific tricks or deceptions, not the general idea of cheating.

It is fairly direct, but not unusually harsh. It is a normal way to tell someone don’t cheat.

Its tone depends a lot on context and intonation:

• said to a child during a game: normal and natural
• said sharply during an argument: more forceful
• said with si us plau: softer and more polite

For example:

• No facis trampes, si us plau. = Please don’t cheat.

So the sentence itself is neutral-direct; the situation gives it its emotional force.

It can be used in many situations where someone is cheating or acting unfairly.

For example:

• in a game
• in an exam
• in a competition
• in any situation where someone is breaking the rules unfairly

So fer trampes is broader than just cheating in games. It can refer to cheating in general.

A simple pronunciation guide is:

• No = noh
• facis = FA-sis
• trampes = TRAM-pəs in much of Eastern Catalan, or TRAM-pes in Western varieties

A few key pronunciation points:

• In facis, the c before i sounds like s
• The stress in facis is on the first syllable: FA-cis
• The stress in trampes is also on the first syllable: TRAM-pes

So overall it sounds roughly like:

noh FA-sis TRAM-pəs

The affirmative command to tu is:

• Fes trampes. = cheat

That sentence is grammatically correct, even if it is not something you would usually want to say.

This pair is useful because it shows the contrast:

• Fes = affirmative imperative
• No facis = negative imperative

So this sentence is a good example of an important Catalan rule: affirmative and negative commands often use different verb forms.