Green’s Dictionary of Slang

Scottish adj.

irritable, easily annoyed.

1812		Vaux Vocab. of the Flash Lang. in McLachlan (1964) 263: scottish fiery, irritable, easily provoked.
1835		G. Kent Modern Flash Dict. 29: Scottish – savage, wild, chagrined.
1848		Flash Dict. in Sinks of London Laid Open [as cit. 1835].

In compounds

Scottish fleas (n.)

syphilis.

1620		J. Taylor ‘Praise of Hemp-Seed’ in Works (1869) III 65: There’s many a Gallant dallying with a Drab, / Hath got the Spanish pip, or Naples scab, / The Galliae Morbus or the Scottish fleas, / Or English Poxe, for all’s but one disease.
1654		J. Taylor Sence upon Nonsence 16: No Bladders, Surbates, Wrench, or Tyrednesse, / No strain, no Scottish fleas, or lowsinesse;.