Green’s Dictionary of Slang

1. (Aus.) a flat-dweller.

1923		letter in Morn. Bulletin (Rockhampton, Qld) 31 July 8/7: Sir,-A ‘Curious Dismal Flatite’ [...] may well adopt a nom de plume [etc].
1929		Catholic Press (Sydney) 3 Jan. 51/2: First Flatite: ‘I’m told you’re leaving here shortly, Mrs. Fox.’ Second Flatite: ‘Yes, we’re moving to a more distant climb!’.
1932		letter in West Australian (Perth) 6 Sept. 10/1: Sir,— ‘Flatite’ states that the Town Planning Commissioner [...] granted the owner of a block of land at Scarborough a subdivision of 50ft. by 120ft. This is incorrect.
1934		Goulburn Eve. Penny Post (NSW) 17 Apr. 4/4: I saw a very natty household jumper the other day. It was worn by a smart flatite who does most of her own chores.
1945		Baker Aus. Lang.
1959		Baker Drum.

2. see flat n.² (4)