Tedesco vs. germanico
In Italian, both tedesco and germanico translate to German, but they are not interchangeable. Tedesco is the common, everyday term for modern Germany, while germanico is a more specialized term used in historical, linguistic, and formal contexts.
Tedesco
A1This is the standard and most frequently used word for German. It refers to anything related to the modern country of Germany, its people, its language, and its products.
Mio fratello studia il tedesco all'università.
(My brother studies the German language at the university.)
Ho comprato una fantastica automobile tedesca.
(I bought a fantastic German car.)
Il mio vicino di casa è tedesco, di Berlino.
(My neighbor is German, from Berlin.)
La cucina tedesca è molto più varia di quanto si pensi.
(German cuisine is much more varied than one might think.)
Il cancelliere tedesco terrà un discorso domani.
(The German chancellor will give a speech tomorrow.)
Molti turisti tedeschi visitano il Lago di Garda ogni estate.
(Many German tourists visit Lake Garda every summer.)
Germanico
B2This word has a broader, more formal, and often historical or academic meaning. It refers to the Germanic peoples, languages, or cultures, which is a wider group that includes but is not limited to modern Germany.
L'inglese è una lingua di ceppo germanico.
(English is a language of Germanic origin.)
Giulio Cesare combatté contro diverse tribù germaniche.
(Julius Caesar fought against several Germanic tribes.)
Il Sacro Romano Impero Germanico è un importante capitolo della storia europea.
(The Holy Roman Germanic Empire is an important chapter in European history.)
La mitologia germanica include dei come Odino e Thor.
(Germanic mythology includes gods like Odin and Thor.)
Lo studioso è un esperto di filologia germanica.
(The scholar is an expert in Germanic philology.)
L'influenza del diritto germanico si estese in gran parte d'Europa.
(The influence of Germanic law spread across a large part of Europe.)
Summary
In short, use tedesco for everyday conversations about modern Germany (the country, people, language, cars, etc.). Use germanico when discussing broader, often historical or academic topics like ancient tribes, the family of Germanic languages (which includes English, Dutch, and Swedish), or the Holy Roman Empire.