this is serious weight

[Theseus]

The term is used when being totally and utterly serious. It means really serious, heavy business/heavy stuff/weighty business.
--This is how it starts: first with the jokes, then comes the heavy stuff.
--This is serious weight & these are dangerous times.:down::angry:

 

[drsiebenmal]

Μια πρώτη ιδέα: βαρύ θέμα.

 

[Zazula]

δεν είναι παίξε-γέλασε

 

[Hellegennes]

Indirectly: "Αυτό σηκώνει πολλή συζήτηση".

Probably, the whole thing (this is serious weight & these are dangerous times) can be translated with "τα πράγματα είναι σοβαρά" or "η κατάσταση είναι σοβαρή". When it's just been realised that things are going to be serious, it can be "το πράγμα σκουραίνει".