Green’s Dictionary of Slang

Freshwater adj.

SE in slang uses

In compounds

Freshwater Bay (n.) [the then adjacent Fleet River; the prison closed in 1842, the market in 1826] (UK Und.)

1. the Fleet prison.

[UK]W.T. Moncrieff Tom and Jerry III v: Welcome to ‘Freshewater-Bay,’ to my new settlement on board the ‘Never-Wag man of war’.
[UK]C. Hindley Vocab. and Gloss. in True Hist. of Tom and Jerry 175: Freshwater Bay. The Harbour of the Fleet-Prison.

2. Fleet Street Market.

[UK]Flash Dict. in Sinks of London Laid Open.
freshwater mariner (n.) (also freshwater seaman)

(UK Und.) ‘their shippes were drowned in the playne of Salisbury’ (Harman), such criminal beggars claimed to have suffered shipwreck or piracy and requested alms to return home.

[UK]Harman Caveat for Common Cursetours in Viles & Furnivall (1907) 48: These freshe-water-mariners, their shippes were drowned in the playne of Salisbury. These kinde of caterpillars, counterfeit great losses at sea: [...] These wyll runne about the countrey wyth a counterfet lycence, fayninge either shypwracke, or spoyled by Pyrates.
[UK]Groundworke of Conny-catching n.p.: [as cit. c.1566].
[UK]B.E. Dict. Canting Crew n.p.: Fresh-water-seamen, that have never been on the Salt, or made any Voyage, meer land-Men.
[UK]J.T. Smith Vagabondiana n.p.: Among the cadgers, there are a number of fresh-water sailors, who never saw a vessel but from London Bridge.
freshwater soldier (n.)

a professional beggar who trades on his spurious reminiscences of battles and campaigns of which, in fact, he has no personal experience.

[UK]Dekker Wonderfull Yeare 5: Thile be found to be most pitifull pure fresh-water souldiers.
[UK]Rowlands Martin Mark-all 15: An idle fellow, and a fresh-water souldier, neuer sayling further than Graues-end.
[UK]J. Mabbe (trans.) Life of Guzman Pt II Bk II 109: Some fresh-water-Souldiers, that were but Novices and yong Travellers.
[UK]T. Heywood Royal King and Loyal Subject I i: Cock, thy father was a fresh-water soldier, thou art not.
[UK]‘R.M.’ Scarronides 91: He is no fresh-water soldier.
[UK]Dryden Don Sebastian 65: You, like a fresh-water Soldier, stood guarding the Pass before: if you miss’d the Enemy, you may thank your own dulness.
[Ire]‘Teague’ Teagueland Jests II 140: A young fresh-Water Soldier newly come out of the Bogs to serve in the late King’s Army [etc] .