Green’s Dictionary of Slang

1. vulgar, ill-bred, mean.

1764		Foote Mayor of Garrat in Works (1799) I 184: mr. sneak: I am your master. mrs. sneak: My Master! you paltry, pudling puppy; you sneaking, shabby scrubby, snivelling whelp!
1814		Austen Mansfield Park (1926) 245: I could not expect to be welcome in such a smart place as that – poor scrubby midshipman as I am.
1832		Satirist (London) 23 Dec. 413/3: The housemaids have kicked up a dust and consider it a very scrubby affair.
1836		D. Crockett Exploits and Adventures (1934) 215: Even the scrubbiest little rascal in the whole drove was disposed to have a fling at their down leader.
1856		B.H. Hall College Words (rev. edn) 406: scrubby. Possessing the qualities of a scrub.
1892		H. Nisbet Bushranger’s Sweetheart 65: I did think as you was more of a gentleman nor to do this scrubby trick.
1913		J. London Valley of the Moon (1914) 82: He don’t like all his horses as much as I like the last hair on the last tail of the scrubbiest of the bunch.
1919		Mencken letter 23 Nov. in Riggio Dreiser–Mencken Letters II (1986) 363: He is here singing the praises of lousy cafes [...] to catch the scrubby tourist.

2. promiscuous.

1969

P. Boyle All Looks Yellow to the Jaundiced Eye 53: A scrubby, smirking pansy.