Green’s Dictionary of Slang

(orig. Aus.) a large piece of excrement; thus groganesque adj.

1975		Woroni (Canberra) 15 Oct. 10/4: We had a party here and some animal left a grogan in the bathtub .
1986		personal communication 9 Oct. [email] I find it hard to believe that you havn’t come accross the term ‘grogan’ in your travels, to use the vanicular [sic] it means ‘shit’. Happy to be informative .
1993		B. Moore Lex. of Cadet Lang. xx: The two most common Duntroon terms for such women are [...] Grogan (common Australian slang for the literal ‘turd’) and maggot.
1997–2000		College Sl. Research Project (Cal. State Poly. Uni., Pomona) 🌐 Grogan (noun) A bowel movement.
1998		Bug (Aus.) 24 Feb. 🌐 George Piggins, called them faeces. But we knew them for what they were – plump, spiralling, smelly, gorgeous Georges in all their groganesque glory.
2003		Urban Dict. 5 Nov. 🌐 GROGAN: it when u take a shit and it hits the water before it snaps off. oi i did the sickest grogan yesterday.