As clear as a whistle.

John Byrom (1691-1763): Epistle to Lloyd. I.

Oh, could I flow like thee, and make thy stream

My great example, as it is my theme!

Though deep, yet clear; though gentle, yet not dull;

Strong without rage; without o'erflowing, full.

Sir John Denham (1615-1668): Cooper's Hill. Line 189.

Besides, this Duncan

Hath borne his faculties so meek, hath been

So clear in his great office, that his virtues

Will plead like angels, trumpet-tongued, against

The deep damnation of his taking-off;

And pity, like a naked new-born babe,

Striding the blast, or heaven's cherubim, horsed

Upon the sightless couriers of the air,

Shall blow the horrid deed in every eye,

That tears shall drown the wind. I have no spur

To prick the sides of my intent, but only

Vaulting ambition, which o'erleaps itself,

And falls on the other.

William Shakespeare (1564-1616): Macbeth. Act i. Sc. 7.

The coast was clear.

Michael Drayton (1563-1631): Nymphidia.