Green’s Dictionary of Slang

1. to go away, to vanish.

1915		F. Garrett diary 23 June 🌐 I remarked to Alex that we would ‘imshi’ some over the dangerous zone.
1916		R.D. Doughty diary 16 July 🌐 Orders to Imski to hand at 4 am. Packed up and left billets at 9.30.
1917		C. Sommers Temporary Crusaders 30 Dec. 🌐 John Turk has ‘imshied’ again all right, and the line is well on ahead of this.
1918		Aussie (France) 4 Apr. 4/1: ‘Gas!’ I repeated. / Our iron nerve – well – imshied. We tumbled over each other in a rush for respirators.
1919		C.H. Thorp Handful of Ausseys 175: The major twigs in a second that the one-star orficer was a gent ’e’d been batman to, just before ’e imshied off from the battalion.
1924		(con. WWI) A.G. Pretty Gloss. of Sl. [...] in the A.I.F. 1921–1924 (rev. t/s) n.p.: imshee. Go away (Arabic).
1944		P. Kendall Dict. Service Sl. n.p.: imshi . . . leave abruptly, scram.
1977		(con. 1941) R. Beilby Gunner 148: ‘What do you mean gone,’ Whiteside demanded. ‘What I said [...] Pissed off. Imshied.’.

2. to hurry someone along.

1915		F. Garrett diary 30 May 🌐 The Jap mortar continued to do good work ‘imshing’ snipers. [Ibid.] 4 June We were ‘imshed’ out of our retreat at an early hour this morning to make room for the road makers.
1918		Kia Ora Coo-ee 15 June 3/2: The M.O. had a look at it, and ordered hot foments, which didn’t make much improvement. So he imshied me off to the Field Ambulance, to have the rest of the nail taken off.