“groan” – English explanatory dictionary

noun a deep cry ○ He uttered a groan and closed his eyes. ■ verb 1. to make a long low noise ○ She groaned when she saw how much work had to be done. 2. □ to groan under a weight to carry a heavy weight ○ The floor groaned under the weight of the gold bars. (NOTE: Do not confuse with grown.)

v. i. [imp. & p. p. Groaned p. pr. & vb. n. Groaning.] [OE. gronen, granen, granien, AS. grnian, fr. the root of grennian to grin. rad.35. See 2d Grin, and cf. 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.

v. t. To affect by groans.

n. 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.” Shak. “The wretched animal heaved forth such groans.” Shak.