Green’s Dictionary of Slang

poorly adj.

menstruating.

1888–94

‘Walter’ My Secret Life (1966) III 487: Her cunt felt very wet, looking at my half-uncunted prick it was covered with blood [...] ‘What’s the matter?’ said I startled for the moment, ‘you’re poorly?’.

In derivatives

poorliness (n.)

menstruation.

1888–94

‘Walter’ My Secret Life (1966) II 418: I saw on one of her stockings unmistakable stains of spunk mixed with poorliness.

In compounds

poorly time (n.)

the menstrual period.

1902

H. Baumann Londinismen (2nd edn).