Zdravím. Jeden můj žák (je to žák jakoby 6. tříd y chodí na nějakou soukromou školu, kde mají rodilé mluvčí, celkově mluví velmi velmi slušně a výborně rozumí) použil slovo „shitty“ ve významu, ve kterém jsem ho nikdy neslyšela a mám trochu podezření, že ho prostě použil nevhodně, ale on celkem s jistotou pravil, že to tak zná… Tak by mě zajímalo, co mi tady na to řeknete – bylo to ve významu jako smutný, řekl něco jako: I am pretty shitty about sth...... Je možné něco takového říct? (popřípadě I feel shitty about something..) Já to znala jen jako že něco je „podělaný“, „na h…“ atd… Do slovníků jsem mrkla a v tomto významu to nenašla, pokud to bylo spojedo s osobou, tak jen ve významu, že ta osoba byla shitty – tedy nějak nepříjemná, krutá apod........ (Urban dictionary…)
Díky!

The usage is correct in terms of meaning, but the style/register is „low colloquial“, and the phrase shouldn''t be used in any normal social context where you wouldn't use hovno in Czech. The example below comes from an online blog where, in English-speaking culture, „shitty“ may be acceptable in a way that other (worse) expletives aren't. So „shitty“ is gaining traction [= používá se čím dál víc] especially among young people, but it's not acceptable in a classroom or other teaching scenario, in a job interview, or in any kind of situation where you would vykat in Czech. Cambridge describes „shitty“ as offensive," Oxford calls it taboo, slang. Longman describes it as spoken not polite. Merriam-Webster says it's vulgar.

Here's an example (written by a 25-year-old woman):

To me, prioritising happiness means that I’ll do things and surround myself with people who contribute positively to my mental health, not holding on to toxic friendships, or continuously doing things that I know are making me feel pretty shitty about myself. (livlivinglife­.com)

„Shitty“ can always be substituted by „bad“, so in the example above , the writer could have said „… that I know are making me feel pretty bad about myself“.

Thank you very much. Yes, I know it's vulgar. When he used it for the third time, I asked him to use something else:) But he is not formal with me (tyká mi…)…
You know – your example sounds natural to me („You are making me feel pretty shitty about myself“), but his sentence didn't…so just to clarify: „to feel shitty about sth.“ is OK (but very vulgar, I know), but „to be shitty about sth.“ is not OK, right? Or it's the thing that you called „low colloquial“? Thank you!

To „be shitty about something“ could only be understood in context, and even then the meaning isn't clear. The intended sense is obviously negative.

1. There may be an element of showing-off in your student's use of this phrase. What youngsters might say on the street in their own company won't necessarily by understood by anyone else.
2. It's also worth bearing in mind that „native speakers“ employed in Czech schools often don't have formal teacher training and sometimes don't know how to teach in a properly structured way, and don't really have a handle on (mít přehled) what it's appropriate to teach students at different levels. They might try to teach their students „cool“ language, but the students may not necessarily understand when certain „cool“ words and phrases are appropriate, and when they're not. ☹️ .

Thanks:) I remember him telling me about an American classmate, so let's hope he didn't hear it from the teachers..... I'll ask him. Anyway, thanks!:)