noun

• (nautical) The rear part (after end) of a ship or other vessel.
  "Holonyms: watercraft < vessel"

adv

• (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."

noun

• (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"."