Webster's Revised Unabridged Dictionary · 1913

groan

groan (grōn) , intransitive verb

[Old English gronen, granen, granien, Anglo-Saxon grānian, from the root of grennian to grin. r35. See 2d Grin, and compare Grunt.]

1.
To give forth a low, moaning sound in breathing; to utter a groan, as in pain, in sorrow, or in derision; to moan.
For we... do groan, being burdened. — 2 Cor. v. 4
He heard the groaning of the oak. — Sir W. Scott
2.
To strive after earnestly, as with groans.
Nothing but holy, pure, and clear, Or that which groaneth to be so. — Herbert

Groan , transitive verb

To affect by groans.

Groan , noun

A low, moaning sound; usually, a deep, mournful sound uttered in pain or great distress; sometimes, an expression of strong disapprobation; as, the remark was received with groans.
Such groans of roaring wind and rain. — Shakespeare
The wretched animal heaved forth such groans. — Shakespeare