Cave aquam in pavimento relinquas, si ventus per compluvium nimis fortis intrat.

Cave is the singular imperative of cavēre, which often means beware, take care, or be careful.

In this sentence, cave introduces a warning:

• Cave ... relinquas = Be careful not to leave ...
• A very literal sense is something like See to it that you do not leave...

This is a very common Latin way to give a negative warning.

After cave, Latin commonly uses the present subjunctive to express a warning about something the listener should avoid doing.

So:

• cave relinquas = do not leave / be careful not to leave

This is idiomatic Latin. English learners often expect a plain imperative, but Latin frequently prefers:

• cave + subjunctive

You may also see cave ne + subjunctive in other texts, but cave + subjunctive by itself is very common.

The subject is an implied you singular.

That is because:

• cave is singular imperative: the speaker is addressing one person
• relinquas is second person singular present subjunctive

So the sentence is speaking to one person: Be careful not to leave water on the floor...

If the speaker were addressing more than one person, the form would be different.

Because aquam is the direct object of relinquas.

• relinquere = to leave
• What are you leaving? water
• Therefore aqua becomes aquam in the accusative singular

So:

• aquam relinquas = you leave water

Because in can take either the ablative or the accusative, depending on meaning.

• in + ablative = location, in/on
• in + accusative = motion toward, into/onto

Here the meaning is location:

• in pavimento = on the floor / in the flooring

So pavimento is ablative singular.

An English speaker may expect on the floor, but Latin often uses in where English uses either in or on.

This is partly a difference in how Latin and English divide up spatial expressions.

Latin in with the ablative can mean being in something, but also being on a surface depending on context. With pavimentum (floor, pavement, flooring), the idiomatic English translation is usually on the floor.

So although the Latin wording looks more like in the floor if taken too literally, the actual sense is simply on the floor.

Compluvium is a specifically Roman architectural term. It refers to the opening in the roof of a traditional house through which rainwater could come in.

So:

• per compluvium = through the roof opening

A learner may not recognize this word because it is cultural vocabulary rather than a common everyday noun in English.

Because per means through and takes the accusative case.

So:

• per + accusative
• compluvium here is accusative singular

Together:

• per compluvium = through the compluvium

Because ventus is the subject of intrat.

• ventus = wind
• intrat = enters / comes in

So:

• ventus ... intrat = the wind comes in

As the subject, ventus is in the nominative singular.

Because fortis agrees with ventus, which is nominative singular masculine.

• ventus = nominative singular
• fortis = nominative singular masculine/feminine

So:

• ventus nimis fortis = a wind too strong / too strong a wind

It is describing the subject, not the object, so it must match ventus, not aquam.

Nimis is an adverb meaning too much, too, or excessively.

Here it modifies fortis:

• nimis fortis = too strong

So the idea is not just that the wind is strong, but that it is overly strong.

Latin often uses the present tense in si-clauses when talking about a real or general condition.

So:

• si ventus ... intrat = if the wind comes in / if the wind is coming in

This does not mean the action must be happening right now only. It can also describe a situation that may occur.

English can handle this in several ways depending on context:

• if the wind comes in
• if too strong a wind comes in
• if the wind is coming in

Because Latin often expresses future or general conditions with the present tense where English might also use the present.

Compare English:

• If it rains, stay inside.

That is present tense in form, but it can refer to a future possibility. Latin works similarly here:

• si ventus ... intrat = if the wind comes in

So the present tense is perfectly natural.

The word order is flexible, but not especially strange for Latin.

The basic parts are:

• Cave = warning
• aquam ... relinquas = what you should not do
• si ventus ... intrat = the condition
• per compluvium = where the wind comes through
• nimis fortis = description of the wind

Latin word order often places important words in positions of emphasis rather than following a fixed English-style pattern. So this sentence may feel less linear than English, but each word is in a normal Latin position.

Yes, in natural English that is often the best translation.

Even though cave literally means beware or take care, the whole phrase:

• Cave aquam in pavimento relinquas

can be translated naturally as:

• Don’t leave water on the floor...

or

• Be careful not to leave water on the floor...

The second version is closer to the Latin wording; the first is often better English.

Yes: compluvium is the clearest Roman cultural detail.

A Roman house of the atrium type often had:

• an opening in the roof called the compluvium
• a basin below called the impluvium to collect rainwater

So the sentence reflects a specifically Roman domestic setting. A learner might understand the grammar but still miss the scene unless that cultural detail is explained.