Pleasantry, n.; pl. Pleasantries.
Etymology: [F. plaisanterie. See Pleasant.]
That which denotes or promotes pleasure or good humor; cheerfulness; gayety; merriment; especially, an agreeable playfulness in conversation; a jocose or humorous remark; badinage. The grave abound in pleasantries, the dull in repartees and points of wit. Addison. The keen observation and ironical pleasantry of a finished man of the world. Macaulay.
Shades of meaning
Fernald has no entry of its own for pleasantry; he lists it under wit.
Where he writes about it:
A pleasing face has good features, complexion, expression, etc.; a pleasant face indicates a kind heart and an obliging disposition, as well as kindly feelings in actual exercise; we can say of one usually good-natured, "on that occasion he did not meet me with a pleasant face." Pleasant, in the sense of gay, merry, jocose (the sense still retained in pleasantry), is now rare, and would not be understood outside of literary circles. — from pleasant
Pleasantry is lighter and less vivid than wit. — from wit