Penetrating, a.
1. Having the power of entering, piercing, or pervading; sharp; subtile; penetrative; as, a penetrating odor.
2. Acute; discerning; sagacious; quick to discover; as, a penetrating mind.
Shades of meaning
Fernald has no entry of its own for penetrating; he lists it under astute.
He lists it without comment; the entries above explain its neighbors.