Green’s Dictionary of Slang

1. to button up a garment; thus sloured hoxter, a buttoned-up inside pocket.

1812, 1823		see sense 2.
1834		(con. 1737–9) W.H. Ainsworth Rookwood (1857) 178: No slour’d hoxter my snipes could stay.
1859, 1860		Hotten Dict. of Modern Sl. etc.
1864, 1867, 1870		Hotten Sl. Dict. 236: SLOUR’D, buttoned up; slour’d hoxter, an inside pocket buttoned up.

2. (UK Und.) to lock up, to fasten.

1812		Vaux Vocab. of the Flash Lang. in McLachlan (1964) 265: slour to lock, secure, or fasten; to slour up is also to button up; as one’s coat, pocket, &c.
1823		Egan Grose’s Classical Dict. of the Vulgar Tongue [as cit. 1812].
1859, 1860		Hotten Dict. of Modern Sl. etc.
1873		Sl. Dict.
1881		Newcastle Courant 9 Sept. 6/5: When we enter the chovey and dub the jigger, slour us in and remain dark until you hear a cat mew.
1990		Tupper & Wortley Aus. Prison Sl. Gloss. 🌐 Slour. To lock a prisoner in a cell.