You have it backwards for unimproved CS, it's an interrupt+lockout, not a silence. Also people are confusing interrupts with lockouts.Originally Posted by Ufalah
Interrupt - Stops the spell currently being cast. Doesn't prevent casting.
Silence - Prevents casting any spell at all, but has a few exceptions like Iceblock & Bubble.
Lockout - Prevents casting any spell from a specific school, including Iceblock & Bubble.