Green’s Dictionary of Slang

1. (US) an outstanding individual; an exceptional creature; a startling event.

1837		‘The Wager’ in Ticklish Minstrel 9: The place that came from must be a rare towser, / For I never before did hear such a rouser.
1846		T.B. Thorpe Mysteries of the Backwoods in Schele de Vere (1872) 225: That ar dare [i.e. deer], I tell you, was a rouser and no mistake.
1868		in Putnam’s Mag. Jan. n.p.: He is a rouser at making punch, I assure you, though he only sips it like a lady himself.
1872		Schele De Vere Americanisms 225: The rouser is not only a man who talks very loud and occasionally yells, but also any startling event or exciting sermon.
c.1905		J. Furphy Buln-Buln and the Brolga (1948) 🌐 Blackfellers mostly goes in for a piccaninny fire – jist three sticks, with the ends kep’ together – but these fellers had a rouser.

2. (Aus./US) a (heavy) blow.

1859		Wkly Varieties (Boston, MA) 3 Sept. 3/4: Sentence — make him hop around [...] under the infliction of five rousers.
1904		Sydney Sportsman (Surry Hills, NSW) 18 May 4/5: The round had little more than started, when it was plain as day light that Smith was sent for. A couple of rousers in the wind and on the point, and the Englishman fell.

3. the first drink of the day, used as a ‘pick-me-up’.

1890–1904		Farmer & Henley Sl. and Its Analogues.
1913		‘J.W.L.’ Slave Stories 37: Give him a good rouser this time, Collings!
1933		‘William Juniper’ True Drunkard’s Delight 228: The tipple itself may generally be known as [...] rouser, or, morning-rouser.

4. (Aus.) a displinarian.

1902

Northern Star (Lismore, NSW) 23 Apr. 3/2: Auld Peter is a bit of a rouser sometimes, but taking him all through he looks after his men very well.

5. a womanizer [? SE arouse].

1941

in E. Cray Erotic Muse (1992) 106: There the boys they called me a rouser, / Fucked his wife and I shagged his daughter, / Shook my prick at his old dog Towser.

6. (drugs) any type of amphetamine or stimulant drug which ‘gets one up’.

1983

R. Klein Jailhouse Jargon and Street Sl. [unpub. ms.].