Reagisce con calma.

Reagisce is the 3rd person singular present tense of reagire, which means to react.

So it can mean:

• he reacts
• she reacts
• it reacts
• you react (formal Lei)

Italian often leaves the subject unstated, so reagisce by itself does not tell you exactly who is reacting unless the context makes it clear.

Italian is a pro-drop language, which means subject pronouns are often omitted when the verb ending already shows the person and number.

Because reagisce clearly shows third person singular, Italian usually does not need:

• lui reagisce
• lei reagisce

You would only add the pronoun for emphasis, contrast, or clarity.

For example:

• Lui reagisce con calma, ma lei no.
  He reacts calmly, but she doesn’t.

Italian often uses a prepositional phrase where English might use an adverb.

So:

• con calma = literally with calm
• natural meaning = calmly

Both reagisce con calma and reagisce calmamente are possible, but con calma is very common and often sounds more natural and conversational.

It suggests reacting in a calm way or with composure.

Con means with.

In this sentence, con calma is a common expression meaning:

• calmly
• with calm
• in a calm manner

Italian frequently uses con + noun to describe how something is done.

Examples:

• parla con sicurezza = he/she speaks confidently
• risponde con gentilezza = he/she answers kindly
• reagisce con calma = he/she reacts calmly

In expressions like con calma, Italian usually does not use an article.

So you say:

• con calma = calmly / with calm

not normally:

• con la calma

Con la calma can exist, but it means something more literal or emphatic, such as with the calmness or in a special context. In the simple everyday sense of calmly, con calma is the normal choice.

The infinitive is reagire.

It is an -ire verb, but it behaves like verbs with -isc- in some present-tense forms.

That is why you get:

• io reagisco = I react
• tu reagisci = you react
• lui/lei reagisce = he/she reacts
• noi reagiamo = we react
• voi reagite = you all react
• loro reagiscono = they react

So the -isc- appears in some forms, but not all of them.

A helpful approximation is:

reh-ah-JEE-sheh

A few pronunciation points:

• gi before e sounds like the j in jam
• sce sounds like sheh
• the stress is on -gi-: rea-GI-sce

So the whole sentence is roughly:

reh-ah-JEE-sheh kon KAL-ma

Yes, but only in the formal sense.

In Italian, Lei (formal you) takes the same verb form as he/she, so:

• Lei reagisce con calma.

can mean:

• You react calmly. (speaking formally)
• He/She reacts calmly.

Without context, reagisce is ambiguous in that way.

Yes. It is a complete and natural Italian sentence.

It has:

• a verb: reagisce
• a phrase describing how the action happens: con calma

Italian does not require the subject pronoun to be stated, so this is fully grammatical and very common.

Yes, but they are slightly different in style.

• reagisce con calma = very natural, common
• reagisce tranquillamente = also possible, often close in meaning to calmly
• reagisce in modo calmo = grammatical, but less natural and less idiomatic in everyday speech

In most ordinary situations, reagisce con calma is one of the best and most natural ways to express the idea.