Noah Webster's New International Dictionary of the English Language

1. (v. i.) To show mirth, satisfaction, or derision, by peculiar movement of the muscles of the face, particularly of the mouth, causing a lighting up of the face and eyes, and usually accompanied by the emission of explosive or chuckling sounds from the chest and throat; to indulge in laughter.

2. (v. i.) Fig.: To be or appear gay, cheerful, pleasant, mirthful, lively, or brilliant; to sparkle; to sport.

3. (v. t.) To affect or influence by means of laughter or ridicule.

4. (v. t.) To express by, or utter with, laughter; -- with out.

5. (n.) An expression of mirth peculiar to the human species; the sound heard in laughing; laughter. See Laugh, v. i.