It blows

[Offroad]

Dear teachers, whether someone is building or doing something that he/she is not good at, then someone says:

It blows. or
It sucks.

So, What does 'it blows' mean? blows what?

and... are there other not-so-polite way of saying that? If so, could you show some examples?

Thank you very much

[Noego]

As far as I know, it's just a figure of speech, it doesn't "blow" anything.

Just like when you say "throwing up", you're not actually throwing anything, it's just a figure of speech.

[Buddhaheart]

If you say or do something wrong, you “blow it” which means you miss a chance or opportunity to do something. For example, John blew his chances when he didn’t prepare well for the interview.

When someone or something “sucks”, it means someone or something is bad or unpleasant. For example, if you didn’t do well in an exam and your friend asked you about it, you would say, “it sucks.” Please note this is a fashionable but informal way of expressing something bad or unpleasant.

[Offroad]

Could you give some more examples, I mean, synonyms with 'it sucks' and 'it blows' ?

Thank you.

[banderas]

Could you give some more examples, I mean, synonyms with 'it sucks' and 'it blows' ?

Thank you.

It sucks=it is bad, not good, unpleasant, unfair. All mean that something is so.
He sucks=he is bad, or not good.

Dude, it totally bites, it stinks= could be alternatives.
A common mistake is to say "it is sucks" which I sometimes hear from non-native speakers. .

[Barb_D]

Also "that rots."

(Note that "it sucks" or "that sucks" are considered quite crude -- and so is "that blows." I don't say those things to my mother. I say "that stinks.")