Player spells like Kick for example will work as per the tooltip - has to be cast as an interruptor which then silences that school for X seconds.
Mob silences I’m certain will work as per original - a blanket silence as described.
Welcome to the forums by the way!
My lv60 Felhunter won over my lv60 mage friend in a 1v1 duel. Those where the days!
An "silence" means it stops the enemy from being able to cast spells for X seconds.
An "interrupt" means it stops the current spell for being casted.
Both exist in Classic (and all expansions).
You can know if a spell is an silence or an interrupt just by the wording of the tooltip.
Example of an interrupt: https://classic.wowhead.com/spell=1769/kick
Example of an silence: https://classic.wowhead.com/spell=13867/improved-kick
Yea, people have always confused Silences and lockouts. Lockouts are spell tree specific (ex you Kick a Holy tree spell, prevents them from casting anything in the Holy tree only) while Silence stops all casting from any tree. Funny because in Cata there was actually a Silence (Strangulate) where if you glyphed for the improve version you could Silence for 2 additional seconds if you caught their cast with it. You could stop a healer from casting a heal for quite a bit with Grip on first cast -> Pet charge to interrupt second -> Pet Gnaw to interrupt third -> Glyphed Strangulate on the fourth cast for a 7 second Silence lmao. It was like a 15second “you ain’t casting shit” chain while you stacked Necrotic Strike to 500k heal absorb. Oh god...
E: and you had a ranged kick on top of that in Mind Freeze LOL
WoTLK had those kind of silences too.
Mages had an talent that doubled their Silence duration (to 9sec) if you caught their cast with it.
Fel Hunter pet from Warlocks same.