Etymology Compare Danish slubbre (“to swallow, to sup up”), and English slabber.
1
To do (something) hastily, imperfectly, or sloppily.
[H]e [Antonio] anſvvered, do not ſo, / Slubber not buſineſs for my ſake, Baſſanio, / But ſtay the very riping of the timec. 1596–1598 (date written), William Shakespeare, “The Merchant of Venice”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act II, scene viii], page 171:
2
Also, Figuratively To cover or daub (something) carelessly with a substance; to stain.
[T]here is no art that hath bin more canker'd in her principles, more ſoyl'd, and ſlubber'd vvith aphoriſming pedantry then the art of policie; […]1641 May, John Milton, “The Second Book”, in Of Reformation Touching Church-Discipline in England: And the Causes that hitherto have Hindred it. […], [London]: […] Thomas Vnderhill, →OCLC, page 42:
3
To slobber.
It grows colder, and grayer, and penguins cry in the night, and huge amphibians moan and slubber.1914, Jack London, chapter 33, in Mutiny of the Elsinore: