Do you think the river seven bridge is big bridge to jump off?

Yes, but you're not allowed to do that

Which bridge over the Severn? (And note spelling of "Severn") There are many bridges from its source in Wales to where it enters the sea below Bristol. There is the famous iron bridge at Ironbridge in Shropshire (Salop) - first iron bridge in the world.

There are two bridges near Bristol which are both big. You would be ill-advised to jump off either of them.

Severn, it's the River Severn. You can jump off almost any bridge.

Which one?

There are two nice big suspension bridges over the severn. You may prefer to jump off Clifton suspension bridge instead.

Did you mean to post this under 'Travel>UK>Bristol? The Severn does not pass through Bristol at all. Bristol has several bridges over the River Avon, and along it's length there are many bridges over the Severn.

I have seen people 'tombstoning' or jumping off bridges to swim in the river in Bristol, but strongly urge you not to. It is a very dangerous practice. Several people have been killed doing this in recent years.