aft

Etymology 1

From Old English æftan (“behind”); possibly originally superlative of of (“off”). See after.

noun

1. (nautical) The stern portion of a vessel.

adv

1. (nautical) 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

adj

1. located at the back of a boat, ship, or airplane

Etymology 2

Clipping of afternoon.

noun

1. (dated slang) Alternative form of afternoon: the time of day from noon until early evening.
   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