Counterspell
1 reaction, which you take when you see a creature within 60 feet of you casting a spell.
Can I Counterspell a creature that completely eliminates component requirement?
Subtle Spell
When you cast a spell, you can spend 1 sorcery point to cast it without any somatic or verbal components.
If the spell is subtle then can I see it’s being cast in order to counterspell it?