Origin and history of punster

"a Conceit arising from the use of two Words that agree in the Sound, but differ in the Sense" [Addison]; "An expression in which the use of a word in two different applications, or the use of two different words pronounced alike or nearly alike, presents an odd or ludicrous idea" [Century Dictionary]; 1640s (apparently in reference to a disguised play on Thames/tame). The word is of uncertain origin.

Perhaps it is from pundigron, meaning the same thing (though attested first a few years later), itself a word of uncertain etymology. Perhaps it is a humorous alteration of Italian puntiglio "equivocation, trivial objection," diminutive of Latin punctum "point." This is pure speculation. Punnet was another early form.

Pun was prob. one of the clipped words, such as cit, mob, nob, snob, which came into fashionable slang at or after the Restoration. [OED]

 The verb, "to make puns," is attested by 1660s, in Dryden. Related: Punned; punning.

At the revival of learning, and the spread of what we may term the refinement of society, punning was one of the few accomplishments at which the fine ladies and gentlemen aimed. From the twelfth to the sixteenth century, it was at its greatest height. The conversation of the witty gallants, and ladies, and even of the clowns and other inferior characters, in the comedies of Shakespeare and his contemporaries, which we may be sure was painted from the life, is full of puns and plays upon words. The unavoidable result of such an excess was a surfeit, and the consequent dégout, which lasted for more than a century. Like other diseases, it broke out again subsequently with redoubled virulence, and made great havoc in the reign of Queen Anne. [Larwood & Hotten, "The History of Signboards from the Earliest Times to the Present Day," London, 1867] 

Old English -istre, from Proto-Germanic *-istrijon, feminine agent suffix used as the equivalent of masculine -ere (see -er (1)). Also used in Middle English to form nouns of action (meaning "a person who ...") without regard for gender.

The genderless agent noun use apparently was a broader application of the original feminine suffix, beginning in the north of England, but linguists disagree over whether this indicates female domination of weaving and baking trades, as represented in surnames such as Webster, Baxter, Brewster, etc. (though modern spinster probably carries an originally female ending). For Dempster, see deem (v.).

Also compare whitester "one who bleaches cloth;" kempster (c. 1400; Halliwell has it as kembster) "woman who cleans wool." Chaucer ("Merchant's Tale") has chidester "an angry woman" (the 17c. had scoldster). "Piers Plowman" (late 14c.) has waferster "woman who bakes or sells wafers." A c. 1400 psalter has yongling tabourester "girl drummer" (for Latin puellarum tympanistriarum).

Also compare Middle English shepster (late 14c.) "dressmaker, female cutter-out," literally "shapester," sleestere (mid-15c.) "murderess, female killer" ("slay-ster"). Sewster "seamstress" (Middle English seuestre, late 13c. as a surname, also used of men) is still in Jonson but was obsolete or provincial after 17c.

In Modern English, the suffix has been productive in forming derivative nouns such as gamester (compare gamer), roadster, punster, rodster "angler," throwster "gambler," etc. But still with consciousness of sex; Thackeray (1850) has jocular spokester "female speaker or spokesman." Tonguester "talkative, loquacious person" seems to be a nonce-word (1871). "American Speech" in 1935 reported that "Singers are now tunesters to advertising writers for vaudeville and other entertainments." A 1798 dictionary of thieves' jargon has yapster "a dog."