Green’s Dictionary of Slang

1. an advertisement or similar statement of charges for board and lodging.

1860		Hotten Dict. of Modern Sl. etc. (2nd edn).
1864, 1867, 1870		Hotten Sl. Dict.
1937–84		Partridge DSUE (1984) 399: [...] from ca. 1855.

2. thus a generic term for poverty.

[c.1786		Grose Classical Dict. of the Vulgar Tongue ms. additions n.p.: Flag of Distress the Cockade of a half pay Officer].
1860		Hotten Dict. of Modern Sl. etc. (2nd edn).
1873		Sl. Dict. 163: Flag of distress any overt sign of poverty; the end of a person’s shirt when it protrudes through his trousers.
1937–84		Partridge DSUE (1984) 399: [...] from ca. 1855.

3. the end of a person’s shirt protruding through a hole in their trousers.

1860		Hotten Dict. of Modern Sl. etc. (2nd edn).
1864, 1867, 1870		Hotten Sl. Dict.
1895		Crowe Aus. Sl. Dict. 29: Flag of Distress, the fall of one’s shirt through the seat of his trousers.
1937–84		Partridge DSUE (1984) 399: [...] from ca. 1855.