Giddiness, folly.

Thoughtless folly, flightiness; fickleness, instability.

Fickleness; folly, levity; an instance of this.

The quality of being foolish or of holding erroneous opinions. Obsolete.

flightiness.

Light-headedness, imbecility; delirium; also folly, foolishness, silliness. Obsolete. rare.

As a moral or mental quality, in various senses. Want of serious thought or reflexion; frivolity. Also (now chiefly), ‘Trifling gaiety’ (Johnson)…

As an attribute of a person: lack of knowledge or sense; inanity; (esp. with reference to a speaker or writer) lack of thorough consideration or…

The state or condition of being vain, in various senses. Foolishness, stupidity. Obsolete. rare.

folly.

Folly; foolish trifling, silliness.

= desipience, n.

figurative. Mental vacuity; lack of ideas or sense; frivolity, senselessness, silliness.

The quality of being frivolous; disposition to trifle, frivolous behaviour, levity.

= impracticality, n.

The fact or quality of being unpractical; lack of practical skill, knowledge, or usefulness. Cf. impracticality, n.

the condition or state of being bird-witted.

The quality or condition of being scatty or scatter-brained.