Mám hlad

Yes, 'Som hladný' is perfectly correct and common. 'Mám hlad' is just slightly more idiomatic in casual speech.

It is neutral. You can use it with friends, family, and even colleagues or bosses in a casual setting.

You can say 'Umieram od hladu' (I'm dying of hunger) or 'Mám vlčí hlad' (I have a wolf's hunger).

It's a linguistic feature of many Slavic and Romance languages where states of the body are viewed as something you possess.

The opposite is 'Som plný' (I am full) or 'Som najedený' (I have eaten/I am fed).

No, in 'Mám hlad', it stays in the accusative form, which looks the same as the nominative for this word.

Yes, metaphorically, like 'hlad po informáciách' (hunger for information).

It's better to wait for the host, but it's not strictly rude. It's very direct.

You say 'Máte hlad?' using the plural form of the verb.

It means 'Hunger is the best cook'—anything tastes good when you are hungry.

Yes, 'Som vybitý' (I am drained/empty) is sometimes used by young people.

You can write 'Mam hlad', and people will understand, but the 'á' is important for correct pronunciation.

It is masculine inanimate.

No, you should say 'Mám chuť na pizzu'. 'Hlad' is for general hunger.