Green’s Dictionary of Slang

1. (US) a soap opera.

1972		Listener 11 May 631: Down to earth with The Brothers, the sudser with everything.
2001		Eve. Herald (Dublin) 21 Mar. 36/2: What is the name of the popular New Zealand sudser set in the local hospital?

2. a romantic film, seen as appealling to a female audience.

1989

Irish Indep. 29 Dec. 22/1: A glut of weepies at the cinema [...] what the trade call ‘women’s pictures,’ ‘tearjerkers’ and ‘sudsers’.