Gender and number of nouns: peculiarities / Particolarità su genere e numero dei nomi

Gender: m. or f.?

There are nouns like "sentinella, guardia" ( sentinel, guard) that are f. although they normally refer to male persons.
Articles, adjectives, participles etc. are also f.: "La sentinella è stata uccisa" ( The sentinel has been killed).

Some derivatives of f. nouns change into the m. gender "donnone, portone, casone..." ( an oversize woman, a gate of a building [literally: big door], a type of farmhouse). See more here

Number: sng. or pl.?

There are words like "news, information, furniture, advice, business, hair..." that are sng. in Eng. but usually correspond to pl. words in It. ( notizie, informazioni, mobili, consigli, affari, capelli...). Examples:

Business is business Gli affari sono affari.
The news from the USA is horrible Le notizie dagli USA sono orribili.
Could you give me some information, please? Per favore, potrebbe darmi alcune informazioni?
My furniture is all made in Italy I mei mobili sono tutti fabbricati in Italia.

Eng. pl. "people" frequently corresponds to It. sng. "gente". Examples:

There were a lot of people around the monument C'era molta gente attorno al monumento.
What do people think about this Government? Che cosa pensa la gente di questo governo?

Indefinites like "qualche, qualsiasi, nessuno" are followed by sng. nouns: "qualche programma, qualsiasi programma, nessun programma." Contrast with Eng. pl. some/any/no programmes.