Facediary

Yes, it is totally fine to say Crap. Though overuse of it may result in a warning.

The guidelines say that swearing is not tolerated, Crap is on the edge of swearing. But not, so feel free to use it. Just remember that fake swearing is not allowed when you use a similar way to swear on purpose.

Also, it depends on the situation, if you say "Your artwork is crap" or "You are so crap at writing." That will result in a warning because your using it in a mean unrespectful way, but if you are saying something like what Fang said, in that context that is fine.