Green’s Dictionary of Slang

1. physical exercise.

1899		Daily Tel. 14 Aug. in Ware (1909) 122/2: Every man after lunch devotes himself to ‘eccer’, which is, in ordinary parlance, exercise. This may take the shape of ‘footer’, or a mild constitutional known as a ‘constitutes’, while if any one lounges idly about he is, of course, a ‘slacker’.
1901		Athletic News (Manchester) 6 May 5/4: I therefore append the meaning of certain barbaric terms applied to current sport by Oxonians — [...] ‘Eccer’ = Exercise generally.

2. (Aus./Irish) homework.

1910		Bulletin (Sydney) 6 Oct. 18/1: Young Jimmy has his back up; he will not haste to school – / All day to sit and whet his wit where tender teachers rule. / He will not do his ‘ecker’ as a decent nipper should, / Nor learn-up Asia’s rivers for his sometime-later good.
1922		Gippsland Times (Vic.) 2 Nov. 5/2: Gorblimey, boy [...] / Duck ’ome, an’ do yore ecker.
c.1940–5		‘Myles na gCopaleen’ Best of Myles (1968) 249: They are the things of childhood and together with the Meccano jersey in purest jaeger, the cogged ekkers and the consumption of neat lemonade.
1972		(con. 1940s) N. Conway Bloods 99: He wasn’t going to let the previous night’s ’eccker’ go to waste.
1981		(con. 1920s) P. Crosbie Your Dinner’s Poured Out! 220: ecker home exercise.
1991		B. Quinn Smokey Hollow 81: Parents warned about ending up in such dead-end jobs if they didn’t do their eckers (homework) and study properly.
1991		R. Doyle Van (1998) 362: D’yeh have all your eccer done now?
2001		G. Coughlan Everyday Eng. and Sl. 🌐 Eccer (n): homework (from exercises).