Difference between Silliness and Fatuousness

SILLINESS vs FATUOUSNESS: NOUN

An act that is silly; a result of being silly.
That which is perceived as silly or frivolous.
The quality or state of being silly.
The quality of being silly; foolishness; senselessness; weakness of understanding; extreme simplicity; absurd or contemptible folly.
A ludicrous folly
An impulsive scatterbrained manner

Craziness, Stupidity, Buffoonery, Lunacy, Frivolity, Foolishness, Tomfoolery, Hilarity, Inanity, Ridiculousness, Idiocy, Fatuity, Giddiness, Fatuousness, Absurdity

Puerility, Presumptuousness, Speciousness, Pompousness, Shamelessness, Sanctimoniousness, Pointlessness, Banality, Pomposity, Vacuousness, Inanity, Vapidity, Silliness, Absurdity, Fatuity

Hijinks, Whimsy, Stupidity, Buffoonery, Lunacy, Frivolity, Foolishness, Tomfoolery, Hilarity, Inanity, Ridiculousness, Idiocy, Fatuity, Fatuousness, Absurdity

Clownishness, Stupidity, Imbecility, Mindlessness, Presumptuousness, Speciousness, Pompousness, Sanctimoniousness, Banality, Vacuousness, Inanity, Vapidity, Silliness, Absurdity, Fatuity

Silliness abounds, with colorful, exaggerated illustrations enhancing the humor.
Launcelot Wake at his most pedantic and schoolgirl silliness.
This is pure silliness on the part of Trump.
Our first Witnness forays really were virtually juvenile silliness.
But following such a rigid, absolute standard is silliness.
Make time for silliness and joy each day.
It was their silliness that made them serious.
That is exactly the rhetorical silliness I despise.
We are done to that amount of silliness.
He loved any kind of silliness like that.

From farming to horticulture to history writing to child rearing, all their experiments tend to prove the fatuousness of most human knowledge.