Green’s Dictionary of Slang

1. a prostitute.

1589		Nashe Anatomie of Absurditie in Works I (1883–4) 14: As there was a loyal Lucretia, so there was a light a loue Lais.
1599		H. Porter Two Angry Women of Abington C3: Mistresse flurt – you foule strumpet Light aloue, short heeles, mistresse Goursey.
1605		Shakespeare London Prodigal B3: I hate a light o’ love, as I hate death.
c.1617		Fletcher Chances I iv: Sure he has encountred Some light o’ Love or other, and there means To play at in and in for this Night.
c.1621		Beaumont & Fletcher Wild-Goose-Chase VI i: One of your London light o’ loves, a right one! Came over in these pumps, and half a petticoat.
1867		(con. 1600s) M. Lemon Leyton Hall I 264: She hath been here and tells me thine old light o’ love, Mistress Leyton, is in town!
1874		‘Ouida’ Two Little Wooden Shoes (1902) 267: You were spared a bad thing, lad; the child was that grand painter’s light-o’-love.
1902		‘Banjo’ Paterson ‘Anthony Considine’ Rio Grande’s Last Race (1904) 67: But a light-o’-love, if she sins with one, / She sinneth with ninety-nine.
1923		‘Bartimeus’ ‘The Look’ Seaways 137: There was nothing about these lights-of-love on which a man could hang either an ideal or a memory.
1938		X. Herbert Capricornia (1939) 339: He goes out huntin’ for his elopin’ light o’ love.

2. a female partner, a wife or mistress.

1868		Sportsman 11 Mar. 2/1: Notes on News [...] Was there not [...] a certain wife [...] one of whose excuses for deserting conjugal bed and board was, that her husband objected to keep the nails of his feet within proper length. After this, who can wonder at this Cincinnati ‘light o’ love’ lady’s eloping.
1868		Sportsman 30 May 4/1: Notes on News [...] To descended from kings and kings’ ‘light o’ loves’ may even be thought [...] to be rather advantageous than otherwise.
1906		Truth (Wellington) 6 Oct. 6/3: Falton [...] didn’t dispute paternity, and voluntarily agreed to pay his light-o’-love.
1907		R. Service ‘The Shooting of Dan McGrew’ Songs of a Sourdough 30: And watching his luck was his light-o’-love, the lady that’s known as Lou.
1932		‘Ex-Légionnaire 1384’ With the Secret Service in Morocco 21: There was no room for sentiment in the espionage game, not even with one’s light-o’-love.