A "hard" brexit is a no deal brexit. So wto rules
A "soft" brexit is a negotiated one. That's how I read it.
Having spent way too much time following this, my understanding is that CU+SM/EEA/EFTA etc are all variations of "soft". No deal = hard Brexit without a withdrawal agreement.
He doesn't want to just walk away in October like the Brexit party and a lot of the conservatives do.
Spot on. First prize for Corbyn is a hard Brexit, but with a proper withdrawal agreement in which the UK adheres to its commitments and international treaties it signed up to, and keeps economic damage to a minimum. I don't believe his customs union plan makes it "soft" though - nor do I think it's a good idea.