From Old English æftan (“behind”); possibly originally superlative of of (“off”). See after.
Meanings
At, near, or towards the stern of a vessel (with the frame of reference within the vessel).
I came safe on board, but I felt anything but easy about the boat and the boy; my thoughts were not where they should be, for every moment I had to give the boat and the boy a look, and at last I saw a sea strike the boat aft, which gave it a send forward and under, and the next moment he was gone. 1886, Peter Christen Asbjørnsen, translated by H.L. Brækstad, Folk and Fairy Tales, page 183:
ga sa deireadh (at, near, or towards the stern) · bg назад (at, near, or towards the stern) · hu hátul (at, near, or towards the stern) · hu hátra (at, near, or towards the stern) · bg към кърмата (at, near, or towards the stern) · ru на корме (at, near, or towards the stern) · mi kei te kei (at, near, or towards the stern) · ga thiar sa deireadh (at, near, or towards the stern) · hu hátrafelé (at, near, or towards the stern) · es a popa (at, near, or towards the stern) · fi perään (at, near, or towards the stern) · sv akteröver (at, near, or towards the stern) · it a poppa (at, near, or towards the stern) · de achtern (at, near, or towards the stern) · ru к корме (at, near, or towards the stern) · sv akterut (at, near, or towards the stern) · fi perässä (at, near, or towards the stern)
A gents' toilet room might be found in a house that caters for the cheaper class of theatrical patronage, where the slangy language of the "goin' to the mat this aft?" style prevails. A gents toilet room is not found in the Southern Hotel. It either "men's" or "gentlemen's". 1898, The Hotel/Motor Hotel Monthly, volume 6, page 27:
There's gonna be an announcement later this aft, but he's targeting vulnerable people like yourselves, alright? 2016, Sally Wainwright, 49:45 from the start, in Happy Valley, season 2, episode 1, spoken by Catherine Cawood (Sarah Lancashire):